I ALWAYS play kennen mid. But if someone decides to be a jerk about it and take mid, then i take solo top.

I usually use these two builds like 99% of the time...

These are the runes i use.. mostly because i use to play mundo before i got to lvl 30... but they seem to work just fine, so i kept them...

Dorans Shield I've never really tried anything to start of with OTHER than dorans shield.. I use to be one of those people who skip dorans and get early items, but this works extremely well.

Mejais Soulstealer This item i NEVER get.. unless i am 2-0 or better on my first or second time going back.

Rylais Chrystal scepter this is a must on kennen in my opinion. it works so good with his ult, its amazing

Rabadons Deathcap this item is prolly like any AP champs "must have" item. but yeah, i like it... makes you hurt so much

Zhonyas Hourglass I personally LOVE this item.. it gives an amazing feeling when you are fed, and get into a team fight.. you pop your ult when the enemies are grouped up and BOOM zhonyas... they all get slowed(rylais) and stunned and they cant touch you for the duration of the zhonyas.. its amazing

Guardian Angel personally, i really like this item. It gives you longer life.. and its AMAZING if your fed and get focus.. cause it puts the opposite team in a "should we focus him still?" type of argument

Abyssal Scepter To be honest.. i dont use this item very much. mainly because i think that the money can go into better things. And usually the game doesnt go that far to where i get this item anyways.

first max out shuriken for last hitting AND harass.

then max out electrical surge (its debatable whether to max out this first, but to me i think if you do max this out first, and do the lightningrush+electrical surge combo, your gunna be pushing the lane white a bit)

lightning rush last, this is pretty much your get-a-way tactic most of the time... but you ALSO can use this in team fights to tag the opponents with a mark of the storm, just to get the stun off

Pros

great CC
bulkyish
great farm
great damage
amazing ult
he is fast
he is a bboy (type /d in game)

Cons

will get focused
CC will mess him up
predictable when using lightning rush on minions
really not that much else

Most of the time during team fights, i stay behind and let the tank or somebody else initiate. But kennen is also a viable initiator.

my favorite type of initiation from kennen is flash+ult+zhonyas... this is just amazing, cause by the time your zhonyas wears off, your ult will be hurting the enemies, and your team would be there to join the fight, and BOOM. usually you win

FARMING IS THE MOST IMPORTANT THING FOR KENNEN

usually i think farming is the most imortant thing for ALL ap carries.

although kennen is a very good harasser, farming is far more important.