It's simple: Everything is an Essence of the Wild.
Everything.
If you lose your four Wilds, you have lost the game, and should probably just concede. Waste no time trying to draw a Wild, if it isn't in your hand to start with a bunch of Mana Ramping, Mulligan.
Please note: upon the release of M14, Primeval Bounty will be a far more important card than things like Terrifying Presence or Withstand Death.
Disciples of the Wild attempts to capitalize on a very potent ability possessed by Essence of the Wild. Once the card is on the field, any card you play after that becomes a copy of Essence of the Wild. This allows you to pay 6 mana for a 6/6... and then start pay 1 to 2 mana for every subsequent 6/6. Needless to say you should have an empty hand after the second turn with Essence on the field.
This strategy would tend to suggest that, until you have a Wild down, preserving creature spells is a good idea. It is not. There are plenty of creatures in the deck, and it hardly takes more than five Wilds to bring down any opponent who didn't have an absolutely sublime start. Pinging for one accomplishes more than one might think with this deck. If you have a spire tracer in your opening hand, put it down and start dropping pins until there's flying on the board.
The copperhorn may actually be more useful as the copperhorn than as a Wild. Perpetual vigilance is the next best thing to having an enchantment that says "creatures you control have vigilance,". This is especially true when you have enough Wilds to force them to avoid blocking the copperhorn, or if you can play the Withstand Death on it.
Skarrgan is a good turn two, as you will likely ping on turn one with the mana ramp creature you put out turn one, and you can still play another ramp in the same turn. A 2/2 blocker and a ramp on turn two is nothing to be unhappy about.
The martyr should do her job early, because later in the game, when there are Wilds on the field, you should have almost no green cards in hand, and 6/6 is highly threatening to anyone without green pro, deathtouch, or indestructibility.
The trading post is a key Wilds generator. Carry around a goat token anyway, but don't forget that for every creature card you discard, you can generate four Goat Wilds once the Wilds are on the board.
Mul Daya Channelers are wonderful ramp, and depending on the top card, their combat prowess is the second best in the deck.
Take note that if Tukatongue or Nissa's Chosen become Wilds, their abilities do not activate. Nissa's ability requires that it dies as a Nissa's Chosen, and the Thallid requires that it die as a Thallid.
The Ambush Viper, on the other hand, is potentially the best way to make enemies with this deck. While you pay two mana to put it in on your turn, putting it in on the enemy's turn and watching your flash 6/6 Ambush of the Wild halt a huge boosted creature or kill a creature the enemy forced through is quite satisfying, and may result in tables tupping the top of your head.
By far the most useful card besides the actual Wild is Asceticism though. If Asceticism is available to you before you play the Wild, then barring a counterspell, you will ensure that you play your first Wild. Those with boardwipe will find themselves in a difficult position unless all permanents are removed, and you yourself need only worry about what enemies have in the way of blockers once Asceticism is on the field.
My own favorite way to win, however, involves having enough damage for lethal in the disparity of the enemy's blockers and my own creatures, and dropping a Triumph of the Hordes in front of them.