Focus on avoiding his q, he cant do much as long as you always have a minion between you and him, although if you do let him auto attack you 3 times for free he will most likely try to reposition you with w to where he can q you.
Hp isn't that bad to build against him considering his W is pretty weak (although his damage is consistent so it isn't the best option), consider building hp if you cant fit any mr into your build.
Also you beat tahm kench by grouping and killing his damage dealers before he kills yours/ stopping him from saving his damage dealers...his whole goal is to make atleast 1 person on the enemy team more useless than he is, either by stopping assassination attempts/peeling or dealing with carries.