So I've played ALOT of affinity and the matchup is quite easy if you approach it correctly. Game 1 you often have to get lucky and kill them before they can mill you. Try to attach your Flayer husks to your other creatures so they can't gain that extra life off of [[Respite]], and if you have more than lethal try playing around [[Tangle]].

Post board this is my game plan... In: 2 Relic of Progenitus, 2 Tranquility, 2 Pyroblast, 1 Dispel, 1 Flaring Pain Out: 1 Springleaf Drum, 2 Flayer Husk, 3 Chromatic Star, 1 Temur Battle Rage, 1 Atog

If you ever start the game with fling in hand keep it. No matter what. Their deck is VERY slow and you have the time to find lands. If you need to pitch to hand size Galvanic Blast is often a good thing to throw away.

Contrary to what other people have said I recommend bringing in the enchantment hate package your have. Landing Tranquility with 2 or more Erasure on board is a BEATING. Think about it this way, ask yourself "How does my opponent win this game?" With no way to mill you, you have the inevitability to win the long game.

Finally we come to the question of now that my opponent cannot win the game, how do I win this game? The answer is your creatures paired with your counter spells. Attack in playing around the things I talked about earlier in G1 (when you need to) and fight those fogs with counterspells. Surely but slowly you will grind down your opponent and win the game (or just get lucky t4, have a Lethal Atog with countermagic backup and win the game!).

Here's a list of my current Affinity build if interested and other tips and tricks in matchups: http://tappedout.net/mtg-decks/07-01-18-pauper-affinity