Kennen is an off-semi-tankey off-carry beast that excels in different ways at most phases of play. He has a very strong early game that makes him one of the best mid-lane champions in the game, but at the same time he can solo-top or partner with someone in bottom. He fills many different roles and is easily one of the best choices for any team composition.

I actually suggest you grab energy runes for your yellows but Mobafire doesn't have them entered :)

That said, AP runes are great as are CDR blues. Reds MUST be magic pen in order for Kennen to be effective early game in any lane.

I like to build him tankey, and late game Ardor gives a nice boost.

A lot of guides will tell you not to buy your e (lightning rush) until level 4...I'm really not sure how they justify the lack of mobility. Lightning rush gives you so much farming capability it's sick. Run through the enemy creeps (maybe even your enemy if they are too close), then w on your way back to behind your creep wave. Now at just level 3 you own this lane's creep.

Ignite/flash is popular, but I like Ignite/Ghost better for him. You can just cover a lot more ground and even use e/ghost to speed up enough that most slows won't effect you enough for enemy champs to catch up.

Use q to last hit creeps, charge up stacks and use w to harrass. E/w to manage creep and for the love of god ward the bushes. It's worth the gold, I cannot stress it enough how much it's worth the gold. Kennen is one of the few champions that can tower dive relatively early and still expect to live. His e makes you FAST. expect to get hit twice, MAYBE 3 times by the tower if your unlucky but if it's for a kill it's worth it for you...as long as you've warded the bushes and don't get ganked.