First off, get in mid. You want to hit 6 as fast as possible and farm malady as fast as possible as well. Keep in mind that when you hit 6 your ultimate hits your opponent very fast with no other champions around.
Hopefully your going back to base with enough cash for your Malady and Move 1 Boots.
Say hello to mid game, head top or bot for a gank. Your AS should be able to pick up a couple stuns from your W's passive. Try to hit both opponents with lightning rush then W, exhaust one and shuriken the other to stun. Ignite is always there if you need it.
Late game is pretty standard because you hit hard with auto attacks, and you should be hitting as much people as possible with your W. Hopefully I will add to this build later, until then, enjoy Kennen for he has one of the strongest stuns in the game.