Hey! Vsauce, Michael here. In this guide you will find a nasty build + guide to Rengar.

+Pros
+Big dmg
+7 spells (When ferocity is full)
+Good mobility
+A bit of Crowd Control
Can go either full dmg or full tank when needed
+Strong snowball
-Cons
-Useless late without bushes or Thrill of the Hunt (R)
-Can't do anything while cc'd if ferocity is at 0
-Without abilities he is weak
-Has many counters

With Rengar on top, you always want to be in bushes, because when you jump with 0 ferocity, your passive triggers and you get 1 ferocity. Be careful for champions like Darius or Rammus, because when you jump on 'em, Darius can pull you and you won't do damage, and Rammus can Q and stun you.

Go always Q, W, E. When playing against meelees.
Go Q, E, W. When playing against lane bullies (ranged).

It's very easy to farm with Rengar since he has a ranged attack (Bola Strike), AA-reset (Savagery) and a AoE dmg (Battle Roar), just AA-reset when you can to keep your ferocity up as much as possible, if you want to push the lane, just AA, Q , W and E if needed. Tiamat is very good in lane if you're against meelees, because you always want to push the lane due to Rengar having a strong wave clear ability.

In solo queue, always start spamming "On My Way" ping when you're about to ult, because it's very hard for your team to notice you when you just suddenly ult, die to 5 people and start crying.

If you're behind, I recommend you bying Control Wards and placing them on the jungle whenever you can because if you can't help your team with kills, at least put down some vision!