For those playing in Magic: The Gathering's Standard format, the recently-released Challenger Decks provide a good base and template for building a competitive deck. For those who want to build up from scratch, may we suggest our Green Fling deck?
A mostly green deck with just a bit of red splashed in, the deck is designed who want to hit the ground fast and hard. In the early game (and we mean VERY early game) it's all about the mana. An ideal first turn is a Forest followed by a Llanowar Elves. That lets you play a Steel Leaf Champion, a 5/4 beater that's hard to block that early into the game, on turn two. After that, it's about going wide fast, then big with combat tricks such as Blossoming Defense and Larger Than Life or tossing your biggest, baddest creature at your opponent's face with Fling. And having Ghalta, Primal Hunter in the deck is just mean when paired with Fling, basically turning the two cards into 12 points of direct damage for as little as 1RGG. For a little added advantage, Skysovereign is in there to give this mostly green deck some aerial firepower while also providing an answer for Karn, Teferi, and the other Planeswalkers you'll probably face. We threw in three copies of Adventurous Impulse as a sort of diet "CoCo" to help you make your way through the deck during the mid-game.
This deck's sideboard is not gospel as it will need to change for you based upon your local meta. The sideboard we came up with based upon our own local meta in Las Vegas finds a concentration towards artifact and enchantment (read: Saga and white removal) hate. Cards like Appetite for the Unnatural and Thrashing Brontodon go towards that end where Crushing Canopy adds an answer for both fliers and enchantments. The additional three Nature's Way are to allow you to snipe against decks that go wide, Silent Gravestone and Deathgorge Scavenger are to protect you from "graveyard matters" decks, and the Prowling Serpopard can be used in place of Steel Leaf Champion during control matchups.
We've goldfished this deck many times and are quite happy with both its consistency and its speed.
Are you running this deck at your LGS? If so, leave us a comment and tell us how you fared!