Not Updated For Current Season
For this build, all your really have to do is keep your distance until you hit with your spear, then leap in and use all of your moves as a kitty :3
This build can also be mainly for healing. At 14 with at least Zohnya's, you'll be healing or around 500 a pop. And at 18, with all the items, it should be around 750-800 with the cooldown reduction from Nashors.
This is mainly for laneing with someone else because at mid, you will be recalling alot due to the minor mana and health regen. Try getting with someone with decent health/armor. They can play more aggressively and if there decent, first blood will be easy.
After you get kitty form, harass with your spear ALOT!! 2 decent ranged hits should bring them down to half health where there you can exhaust and destroy with kitty form using pounce, takedown, swipe, and if that doesnt get them, turn back to Nid and spear or auto attack depending on the ammount of health. Takedown does more damage the less health the victim has so use this to your advantage when in team fights!
Also, when laneing with someone who can place spawns (Teemo, Heim, etc.) place your trap along with there spawn, causeing more damage due to the ammount of ability power you should have.
Well i hope this helps, with this build, i rarely go negative. which as long as you can aim somewhat decent with spear, you should be fine (: