This is a deck I play casually on MTGO. I've found it's pretty flexible in the current standard enviroment.
Against Humans - If the humans are setting up quickly, work your way to a big blocker like Mina and Denn or Gitrog, then draw agressively using Painful Truths, Ob Nixilis, or clues from Tireless Tracker for your Radiant Flames and burn them all. If you don't have your big blocker, a Sylvan Advocate homegrown with Retreat to Kazandu will do the job, but don't overload on counters and watch out for Declaration in Stone
Against Goggles - Your lifegain is your best friend here. If you expect goggles, save your Kolaghan's Command for them, and keep a Den Protector around if you can to pick it up in case they drop the goggles again.
Against Monoblue Brains - You have a few tools to hold off this deck. First off, if you can keep your life total at more than double the instants and sorceries in their graveyard, their combo won't be able to straight-up kill you, so Retreats should be emphasized towards life gain. Second, you need at least one creature (and preferably two or three) with more toughness than your opponent has (Islands +1) to avoid getting wiped out by Island + Engulf the Shore. By balancing these two variables, the brains player can be beaten.
Against Eldrazi - Recursion and lifegain are your best bet. Carefully calculate how many swings you can take on the current board and if your opponent drops Reality Smasher on the current turn when choosing blockers. Sometimes it's just better to take the damage to your face and gain that life back from landfall, other times you just need something bigger than a 6/6 to deal with a worldbreaker.
Against aggro - The buck usually stops with Mina and Denn, which can easily be grown to match up with most threats with the help of an earlier Retreat to Kazandu. Kill big threats with Ob Nixilis or Lightning Axe, and try to save your Radiant Flames for a 3-for-1 unless your life is on the line.
Against control - Resolving your Painful Truths should be your first priority. Your creatures are big enough that you can win the game with only 1-2 on the board, and you can play around the format's main removal (Languish - get your creatures up to 5 toughness ASAP; Grasp of Darkness - bait it out with a Sylvan Advocate and recur it with Pulse of Murasa/Den Protector; Ultimate Price - use your multicolor legends)
Combos - Mina and Denn with Retreat to Hagra can either slowly drain 2 life per turn by picking up and replaying lands, or can give themselves (or another creature) the sweet combination of Trample and Deathtouch, ensuring that damage goes through when you swing.
Sylvan Advocate + Retreat to Kazandu can make your advocate bigger than the average Advocate. The difference that a +1/+1 counter makes in this Standard can be dramatic; just don't overdo it. After the 2nd or 3rd counter, lifegain often proves the better option since you can keep the lifegain if Advocate gets removed.
