This is my first guide / build.
I play in the Brazil server, My english is not bad but not good, so if you understand anything say on the comments, well, when I purchased twitch, I played on him and I liked !
I prefer he to get a "No countered attack damage carry"
He is awesome!
This build is for someone is playing as twitch recently, and want to learn some things.

Pros
Funny to play.
In the team fight will help your team.
Good early, middle and late game.

Cons
Hard to master
Not have a good escape like Vayne or Tristana.
In the late game will fall against Vayne or Tristana.
Needs a support to be an twitch.

Doing the last hits, you will not push the lane and will get more farm.
Last hits need master!

Your team will help you! If a assassin is going to kill you, your team will need to kill him VERY FAST!.
You stay longer, longer because your ultimate you help you to kill everyone, and your Q will help to kill who run!.
Your team need TANK to you get OK.
If you understand, I prefer a Malphite, Jarvan IV some of this will help you!.
Say to your jungler gank three times and you get two or more kills is fine.