Hey everybody this is a build I use quite often on twitch, witch can be amazing..Im not going to explain skill orders because that is often decided on on how you play twitch
Runes: The runes i picked are for extra crit damage, some extra health from the seals so you might survive abit more if you get focus's, glyphs of magic resist for abit more survivabilty on twitch :)
Masteries: I go for 21-0-9, For the extra damage, Crit dmg mostly Since there is nothing else you could use, Also you could go 9-21-0 or 0-21-9 for more survivability but i choose 21-0-9 Because if you play twitch right your not going to need it.
Summoner spells: Alright i use cleanse and exhaust heres why
Cleanse: WILL save you so many times you won't regret it, Get hit by ashe's arrow? cleanse, ambush there you alive :)
Exhaust: I bring exhaust mostly for the extra slow in laning phase, and to disable a dps during a team fight.
option 2 : Flash could also be a good spell for twitch, for that little extra space when your running so your stealth will kick on
Item Build: Here is the best part, my most games will last till where you get to phantom dancer and it ends.. But it if your game lasts longer be sure to pick up a black cleaver or another inf edge to keep 100% crit, you can sell the avarice blades if you need extra cash for items, But i usually keep 1 for ghostblade, For the last inf edge you will need to sell one avarice atleast.