Welcome and this is my Kha´Zix Jungle Guide. I play him usually in aggressive teamcomps or when i have to solo carry because i dont think my team is that good.

You start at blue or red depending on their Jungler. For Example they have Maokai? You start Blue but if they have Lee Sin you start red try to get big pull from bot or top and ward it that you know where Lee is.
Then u clear your jungle and instantly Gank mid or bot/top depending on what is better for you.
When you gank you try to dont waste your e ( wait for your Laners to engage ) at the start you run at him void spike him q him and if he still lives just e towards him try to spamm q and w till hes dead.

In the most cases you will try to pick up a Carry before the Teamfight starts.
If you fail you have to wait in the Fights till one of them is isolated and just poke with yor w meanwhile.