Twitch is a powerful, squishy, stealthy, AD Carry champion.I have never considered playing AP twitch and I never will. He is also one of the best gankers in the game. People often overlook his ability to grab a quick pentakill with a quick 5 shots. Now it's not as easy as it sounds but i've pulled it off once or twice.

I take a standard AD Carry build for my runes with flat Armor Penetration Marks,flat Armor for Seals, flat Magic Resist for Glyphs, and Armor Penetration Quintessences.

I build 22 offense and 8 defense here. Twitch is undoubtedly a squishy little rat so you have to beef him up a bit in his Masteries while mainly focusing on attack power. There's no way you could go without Lethality . It will help a lot early game and Vampirism will stack with your Doran's Blade giving you 6% Life Steal to start out with leading you to better sustain and more farm.

I was sketchy on this build at first but it has proven to get me fed a majority of the time and it will give you a great mid-end game. Without a doubt grab Black Cleaver as soon as you get your Berserker's Greaves before people begin stacking armor, this way the black cleaver should deplete most of the little armor they have to begin with. I like to build multiple core items at a time so after i get my Zeal I grab a B.F. Sword to begin building Infinity Edge before that you have to finish off your Phantom Dancer. I grab Bloodthirster after the Infinity Edge And finish off with some extra health and an unbearable chasing ability with a Frozen Mallet

I max out my Expunge first because this is without a doubt your best last hitting ability early game on champions. You take your ulti at 6/11/16 and then finish your Ambush and Venom Cask last. Although this is helpful in ganking it's not really necessary and it gets the job done at level 1.

You guys probably think i'm an idiot for picking up Clarity on twitch but he is in fact a really bad mana chomp pretty much throughout the whole game. Just when you get your six stacks of Deadly Venom on that annoying little Teemo you realize your 30 mana short of you Expunge and the punk manages to retreat back to his turrent. I also take Ignite in addition to your Deadly Venom because it gives you a much bigger chance at first blood.

Pros
Massive Damage Output
Good Escape
Good Ganker
He's a Rat :D
Cons
Squishy
Not the best farmer
He is kind of useless in team battles

Thank you for reading my guide, I wrote it out of complete boredom and my decent amount of knowledge on Twitch. He was in fact the first champion I ever played and that I have probably played the most although nowadays he is more of a rare pick by my standards. Please comment telling me what you think and vote if you think I deserve it,