Kench's early harass damage is insane. Especially because you will max your main poke first, W. Now you may be confused. Why your W? Why not Q first? It is simple! It is a lot of damage, it can clear waves with ease when maxed, its splash damage is deceptive, unlike your q it benefits from upgrade cooldown and it is a great dueling tool! When your laner all in's you, assuming both of you are level three, play it smart and abuse your passive. After three stacks they will take more damage from you, your q becomes stun and your w can swallow the champion, dealing a percent of their max health in magic damage. This makes you an insane duelist and tank! During a fight, try to make sure 80% of the time they reach 3 stacks. The most damaging combo is to get them to 3 stacks, q them to stun, throw in 2-3 more basic attacks and swallow while going towards your tower. The last part is for two reasons, if the wave is resetting you will throw them into a wave of minions ready to feast with you and gives them less space to run if they so wish! Focus on farm early and start harassing when you hit around level 3 to 4 as your mana costs are heavy in the beginning, but become non existent later.