okay so i was playing with twitch for quite some time going AD AS just like every one seems to do now a days... it has a good output on kills and assists but became hard to find interest in being twitch in a team fight.
i found a way to change this...
my favorite thing about twitch is
Expunge. pushin 500 AP expunge is a huge explosion at 18 team fight with one stack on each character that is still a significant blow in the pace of the fight. but with expunge i believe is a relative longer CDT... this is where frozen heart and Nashor's Tooth work in giving u 55% CDR is the key to this Twitch. not to mention frozen heart helps u in not being quite as squishy towards DPS champs at least while also giving u some more Mana to work into your expunge game.
i'm not a professional nor do i always do great when i play but when it comes to how to build a champion i know who to listen to and who is blowin smoke...
to be an effective twitch player i feel this build is ur way to go...

your ult is very useless in this build you will notice this in game but
your expunge is going to dominate squishies and definitely put a dent in tanks due to your magic pen you gain from your void staff.

thanks for reading guys let me know after playing this build of twitch what u think. give it a couple games because it is hard to learn how to play in this manner.

HF And GL!