Muktol

I will keep "Manamorphose" at the moment until I have done some testgames (which will take some time, at the moment I'm more like building decks than playing them :( ) but having a good cantrip is always a nice thing.
"Foundry Street Denizen" as well as "Kruin Striker" could be an option instead of "Essence Warden" if something more aggressive is needed. At last options to think about, ergo sideboard it at the moment.

Oh, completely forgot to built the right landbase. The defenders where removed and some proper lands where added ^^
"Brighthearth Banneret" was a real good tip as it not only lowers the costs of "Brighthearth Banneret" but also "Bramblewood Paragon", "Champion of Lambholt", "Ogre Battledriver" (now sideboarded, against decks I feel I would need haste) and also "Hunted Troll" (sideboarded against decks that don't feature enough creatures on their own)
I'm not so sure now that "Manamorphose" will do a proper job here, I'm thinking of exchanging it against "Rampant Growth" 4 to8 (e.g. Harrow) or "Mercy Killing" to get some removal.

Looking good now.
"Elvish Archdruid" might be an option instead of "Vine Trellis" if you need some more mana.
"Tribal Unity" or "Untamed Might" might be interesting to put this mana to use and introduce the "pay x" spells (Though "Stonewood Invoker" can also use the masses of mana)
If you want to I also can give your white deck a look, perhaps I have some budget friendly ideas ;)

There are some ways to play elf-decks, agro, combo, swarm, there are even some sub-tribals like elf-warrior decks.
Question is, how do you want your deck to win, which legality do you prefer your deck to have, budget and color (important for combo-decks as most of them add some blue cards)
Personally I'm no big fan of deck that feature an enormous amount of different cards (Save highlander/ EDH but that's a different story ;) ) because you loose continuity through that. If you need and want to draw e.g. "Elvish Archdruid" then use him 4 times. The more different cards you use, the lower is the chance that you draw the spell you need in a certain situation.

Basically there are some cards that many elf-deck feature:
"Glimpse of Nature" ...elves are cheap, you have enough mana and this spell helps you not to run into card-problems.
"Elvish Visionary" ...carddraw
"Llanowar Elves"/ "Fyndhorn Elves" ...simple mana creature
"Priest of Titania" / "Elvish Archdruid" ...if you need some more mana
"Joraga Warcaller" ...pumps swarm decks
"Imperious Perfect"

The rest depends on how your deck should win.

Greetings
Muktol

When using decks with ability's like Kaalia of the Vast (I wouldn't call it an built in "I win" button, but it's not far from that) I would use spells and equipment that protect this card. "Champion's Helm", "Lightning Greaves", "Swiftfoot Boots" and "Mask of Avacyn" are good examples for cards, that protect your commander and they are available to all colors.
Your deck features a very high number of creature enchantments, something I would recommend against. Commander decks use a lot of removal, exile or mass removal. Enchanting a creature might seem like a good idea but a single removal spell from your opponent will cost you the creature and the enchantment. If you want to pump your creatures use effects that stay on the board after a board swipe like artifacts or 'normal' enchantments, if you want to pump a single creature use equipment (artifacts).Global enchantments are OK, but don't forget that you're not playing a normal deck here. "Ghostly Prison" might look good but if you're not up against a mass-token deck your opponent will either have enough mana to attack you anyway or have a way to play around this. "Mana Leak", a cheap and very good counterspell in modern losses it's effectiveness in commander due to that fact that paying {3} normally only makes you laugh.
You should also look for some more removal spells. Black has some very good point-removals while white gives you access to some very potent exile spells.
Last, carddraw. The best color for carddraw is blue, but black also has some very good spells here, if you're not too picky even red can provide you with some good stuff.

I hope I was able to help you a little bit in general, if you have any specific questions, feel free to ask.

Greetings
Muktol

*like*
Try to keep the number of different effects like trample, draw cards, 'whenever enters the battlefield' effects low and focus on cards that are rather easy to understand. Beginners don't want to learn a ton of cards and effects after they already have their head smoking from learning the basic rules. Try to use cards 4 times and don't throw in to many 1-offs.

'Search your library for XYZ' effects, like "Elvish Harbinger", are pure horror for a beginner. Put cards that will make the deck stronger into the sideboard. Sideboarding will be an advanced rule I wouldn't explain to a player before he really knows the basic rules. I would nevertheless built a sideboard and add cards that have advanced rules/ effects. This helps you to keep the deck together and add some more fun to it when it's user has already played some games.

Greetings
Muktol

A short deck description would be fine.
I would remove "Skithiryx, the Blight Dragon". If your opponent manages to stall your plan until T5+ then something has gone extremely wrong and even Skithiryx won't be able to help you. "Wild Defiance" could be an interesting option instead, also a 3rd "Vines of Vastwood" or "Ranger's Guile"
And playing "Blighted Agent" with only "Breeding Pool" to cast it seems a little bit risky. I would reduce the number of "Verdant Catacombs" and add some "Misty Rainforest" or "Polluted Delta" and 1-2 islands.

greetings
Muktol

Pretty uncommon cardchoices for a G/W enchantment deck.
A little deck-description would be fine :)

Some suggestions that came into my mind:
Remove "Scute Mob". It's ability will almost never trigger as want to be as fast as possible and don't use any ramp. Normal calculations say that you can put a land into play every turn for the first 3 turns, and then an additional land every 2-3 turns.
A card play by almost every enchantment deck that features white would be "Ethereal Armor". It's cheap, it's good and it can only get stronger.
"Rancor" can be a real bitchy card for your opponent. +2/+0 and trample for your creature and a really tough one to get rid of.
"Helm of the Gods" was added recently but it's as good as "Ethereal Armor", maybe even a little bit better, because you don't loose it like the enchantment when the creature it's attached to dies.
Last, "Spirit Mantle" can be a real finisher as it allows your creature to bypass your opponents defenses.

Some additional suggestions:
"Spider Umbra", "Abundant Growth", "Keen Sense"

Edit:
Forgot about "Gladecover Scout". With only ~0.2$ per card it's pretty budget friendly and one of the best basic cards for each 'normal' enchantment deck.
"Aura Gnarlid" could also be an option but it features no hexproof.

Greetings
Muktol

I have done a revision of the 'Vampire Onslaught' deck that was released with Innistrad. (http://www.mtgvault.com/muktol/decks/vampire-onslaught-revised/)

Some suggestion based on the deck mentioned above and my own R/B vampire deck:
Personally I hate to see that legality get's messed up by a single card. If you play the deck only at the kitchen table that might be OK, but perhaps you someday want to take your deck to a local tournament and then this will cause problems. Especially if you don't play them as 4 times but only twice, like "Dark Ritual" here.

The basic question is 'how do you want your deck to behave'? There are some possible ways for vampire decks: agro (control), combo, mid-/lategame. The most common will be agro and I will refer my suggestion on that.
"Blade of the Bloodchief" is an extremely good equipment for vampires. Every equipped vampire will get 2 +1/+1 counters when something dies, and that for only {1}+{1}
I would also include some additional removals as vampires (like many tribals) normally need support to make them effective. "Gatekeeper of Malakir", "Dismember", "Go for the Throat", "Tragic Slip" or "Doom Blade" would be the basic choices, but you also could take some discard like "Distress" or "Duress"
Last, I would take a look at some carddraw/ library manipulation spells. The best choice here would be "Read the Bones" or "Viscera Seer". This allows you to ensure that "Vampire Nocturnus"'s ability will be active when you need it to. Shuffling lands that you don't want to draw under you library is always a welcome option.

Now comes the question what to remove.
I would sideboard/ remove the following cards: "Blood Artist", "Child of Night", "Quag Vampires", "Exquisite Blood" and "Sanguine Bond". The enchantments belong more into a combo deck, while the rest is either to situational (many creatures have to die) or just to expensive (multikicker)
"Malakir Cullblade" might have a future when combined with "Blade of the Bloodchief" but the chances of drawing those two cards and then have a removal on my hand to activate it would be rather low.
I would also remove 2 of the 4 "Bloodline Keeper". He has the same mana-costs as "Vampire Nocturnus" but when having a Nocturnus and a Keeper on your hand you always want to play the Nocturnus in this deck.

Greetings
Muktol

"Lightform": The casting of this spell (one colorless and two white mana) counts for prowess.
The 'manifest' ability reads like this: "To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.". So the card you manifest isn't cast it's just put into play, thus no activation of prowess.

"Myth Realized": The casting of this spell (one white mana) counts for prowess.
The first ability puts a lore (not a +1/+1!) counter on the enchantment. It's an ability and thus doesn't count for prowess.
The second ability changes the type of the card from enchantment to creature. It's an ability and thus doesn't count for prowess.
"Myth Realized" is already on the battlefield, it just changes it's type, so no "enter the battlefield" effects will be activated.

If you want to know more about casting spells, ability's in general, special ability's like deathtouch and so on (prowess wasn't added when I recently checked), you should take a look at the complete magic rules book.
There are 2 different versions, one short version for beginners (http://media.wizards.com/images/magic/resources/rules/EN_MTGM14_Rulebook_LR.pdf) and a full version for all those who want/ need to dig deeper into the rules (http://media.wizards.com/images/magic/tcg/resources/rules/MagicCompRules_20140601.pdf).
Both links belong to a PDF file from the official magic website. The link to the site would be http://archive.wizards.com/Magic/tcg/article.aspx?x=magic/rules

Normal equipment decks are trying to be as fast as hell, because they can be overwhelmed rather easy by big creatures or mass-decks. So the question will be 'how fast do I want to play this deck?'
A good equipment will give you +x/+y for x+y mana (play and equip). For example "Bonesplitter" gives +2/+0 for {1}+ {1}, Shuko gives +1/+0 for {1}+ {0} and "Bone Saw" gives +1/+0 for {0}+ {1}. If you rely on getting a creature equipped (preferably with something offensive) I wouldn't only play 1 good equipment but try to get some more. Personally I would remove "Avacyn's Collar" and sideboard "Basilisk Collar" to get some more aggressive equipment's in. Plating also depends on how many cheap/ fast equipment/ artifacts you got in your deck. Plating equipped on an Ornithopther can easily kill your opponent (even if it might take some time without further support)

*like*
I'm missing some of the good (and not that expensive) cards and equipment's:
Cranial Plating (~1,3$ /card), Bone Saw (~0,2$ /card), Shuko (0,4$ /card), Swiftfoot Boots (0,5$ /card)
"Dispatch" (~1,3$ /card) can be a real good removal here.

Greetings
Muktol

Why not use "Kiln Fiend" or "Nivix Cyclops" when playing within modern-legality?
I would put "Twisted Image" into the sideboard because most of the creatures in magic have symmetric power and toughness. If it's for the cantrip, there are other cards you could use here, just do a quick cardsearch for 'text' + 'draw a card' + red + blue

Greetings
Muktol

Lightform will trigger prowess, as well as Myth Realized will, when it enters the battlefield. But that's it then.
Myth Realized gets a lore counter whenever you cast a noncreature spell and you then can pay {W} to tun it into a creature until end of turn, but the 'transformation' itself won't trigger prowess effects.
The same is true for the card manifested with lightform. You activate the ability of the face-down card, gained by lightform. But thats an ability and no spell is cast here.

Why do you think "Myth Realized" would trigger prowess?
Prowess is activated by non-creature SPELLS, activating "Myth Realized" uses its ABILITY, big difference. So the only time this card triggers a prowess ability is when it's cast, and thus enters the battlefield.
Worse, activating wouldn't even trigger enter the battlefield-effects because the card is already on the field. It just changes it's form.

OK, so the target is a standard R/W agro deck that focuses on prowess. Removing the U (blue) part may have lowered the chance of getting through your opponents defenses but we will take a look at that.

First I would change some numbers:
+1 "Bloodfire Expert"...good and aggressive, especially when combined with evasion or trample
Sideboard "Seeker of the Way" and increase to 4...I don't know the decks that re around standard at the moment but lifgain is an option I would always put into my sideboard and use when needed.
Remove "Student of Ojutai"..."Seeker of the Way" is the better choice here and were putting that one into your sideboard
+ 1-2 "Zada, Hedron Grinder"...tough the copies don't count for the prowess ability he's still a very strong supporter. Legendary, though don't use more than 3 of him in a deck.
That would be it for he creatures, now to the support spells.

I would concentrate on some cheap buff and protection spells here, and perhaps some removal.
+ 1-2 "Artful Maneuver"...with rebound it fits perfectly into a prowess deck.
-1 "Kindled Fury"...to get room for "Defiant Strike"
+2 "Defiant Strike"...+1/+0 doesn't sound to good but it allows you to draw an additional card and that can be worth it
-1 "Temur Battle Rage"...finisher, 3 should be enough
+1 "Titan's Strength"...best cheap buff spell red has to offer at the moment
-2 "Trumpet Blast"...I would concentrate on cheap spells that buff one creature.
-1 "Lightform"...lifegain, either remove or sideboard
-1 "Myth Realized"...with only one copy it's not consistent enough. If you draw and play it e.g. on T4 it will be hard to make a valuable 'creature' out of this. Also it doesn't benefit from prowess
+ 1-3 "Feat of Resistance" or "Center Soul"...protection will always be important. One the one hand you can protect your creatures from getting shot away, one the other hand you can help them to get through your opponents defense. A creature with protection from white can't be targeted by white spells (this also counts for your own spells) but it also cant be blocked or damaged by white creatures your opponent controls!

I hope I was able to help you a little bit.

There are millions of different decks out there and the answers for your question depend on some points:
What legality do you want this deck to be built for? At the moment it's nearly standard, the only card ruining that would be "Izzet Guildgate". if you want to play on a beginners tournament or FNM then it will have to be standard legal. If you want to play with your friends then it will either be modern or 'use what you have' aka kitchen table. Should this deck be competitive or do you just want to play with your friends?
What strategy do you want this deck to have? At the moment it looks like an aggressive and fast built that focuses on the 'prowess' ability of many creatures.
Are you willing to buy/ trade for new cards and what is the budget for new cards (per card or for all cards)?

And last, have you already played this deck and ran into some problems with it? If yes, what where those problems.

A short description and some details on what you need help with would be nice. Strategy, legality, budget and so on.
Also some deck-tags, including e.g. "Help", would be helpful.

Greetings
Muktol

*like*
Some suggestions/ Ideas:
When playing "Æther Vial" use a whole playset. A single one won't do much because the chances of drawing it at the beginning of the game are extremely low, so no real consistency. And if you draw and play it e.g. T3+ it will become pretty useless because it takes some time to get it to 3 counters (your ideal number for this deck) and that's a time you normally don't want to wait.
Personally I'm using "Vines of Vastwood" or "Ranger's Guile" to get a little bit more protection from removal.
If you want an alternative for "Burst Lightning" you could take a look at "Searing Blaze".

Greetings
Muktol

*like*
Why no "Assault Strobe"?
If you don't need the cantrip I would change from "Dragon Mantle" to "Madcap Skills".
And just for information (I'm sure you will know this, but others who might look at this deck might not) using "Steeling Stance"' forecast won't trigger heroic as it's a ability and not a casted spell.

Greetings
Muktol