So, what does this deck do? It's basically mono green Storm. Ever seen how Legacy Elves plays? It's basically like that except I don't need to wait for 2 other Elves for Heritage Druid. My commander, Seton, allows all my Druids (which are basically all my creatures) to become Llanowar Elves the turn they come in, so I get a lot of mana early on. Once that happens, I can easily start stomping on my opponent and force them into panic mode before they have set-up.
Superstars (that aren't obvious):
This guy is probably the primo removal target in my deck. At least, during the second and subsequent games. As I said before, my commander lets my Druids tap for mana the turn they hit the field which means they can be used to cast more Druids. This card makes sure that I have that next Druid in my hand. If I fail to draw enough Druids, I can always just remove a player from the game by stealing all their lands.
This is a magic time machine that warps you from turn 4 to turn 6 (at least). That in itself doesn't make it very magical, but the fact that the Forests come in untapped, meaning I can follow this up with more ramp spells or more creatures (which are basically ramp spells in this deck).
Seeing as my commander only costs 3, playing him after a boardwipe is not that much of an issue (much easier if I have Aluren out). Even if I tap out in order to play both him and this, I can probably get most of my boardstate back in the following turn. If it happens again, this card has flashback and I can just recur my board a second time.
So yeah, this is one of my favourite EDH decks. It's not the cheapest to build due to cards like Gaea's Cradles and Regal Force (although I use a gold-bordered Cradle because no one here cares) but it is really fun and quite competitive. If you're looking for a mono-green competitive EDH deck, this one is a great place to start.