Not Updated For Current Season
(This build is for v18.104.22.168: [Ultimate] Now gives AD instead of AS and has attack limit)
UPDT[23-12]: Infinity Edge before 2nd PD (if it lasts that long)
UPDT[25-12]: Changed boots (AS to Tier5 MS), ideal to get more kills everytime you see lowhealth enemy GO for it!
I train Expunge first to level5, then Venom Cask and finally I finish Ambush.
Expunge can give you a lot of kills, Venom Cask will help you getting more stacks so you can finish with Expunge.
Finally, Ambush because you can hide, wait 10 seconds, and call it again.
Ofc, Spray and Pray everytime you can level it.
I choose to do The Black Cleaver before finishing Phantom Dancer because you with your Q and Zeal you can get a good AS boost, imagine AS + Dmg + Armor reduction early ingame and you can get very nice number of kills even before lvl14.
After 1 or 2 kills you can finish Phantom Dancer easily, so the order is: Zeal -> BC(complete) -> PD.
Madred's Bloodrazor is VERY useful on Twitch because it works very nice with your ultimate.
If you can get Infinity Edge it'll bring you many kills at a late-game, actually, you will start it most of the times but probably won't finish it, if you do then mass damage is coming, just position well!
If it really lasts this long, then finish second Phantom Dancer it means: YOUR TEAM WON! Just don't die and wait for the teamfights while defending or attacking!
If you face a strong mage on your lane, you can buy a Negatron Cloak after boots.
If you face Jax, I recommend you to buy Sword of the Divine before finish the 1st PD.
(Don't waste money on armor, since you can kill em before they even understand that you're shooting em, I just use MR because with if you get stun (you can use cleanse) but you get like 2-3 spells in couple seconds and you lose a lot of health, that makes you go out of lane)
Armor is useless since you already have a nice boosts from runes.
Cleanse is used to clear you from stuns (not slows tough, you can click Q Ambush and Flash, no need to waste cleanse [depends on enemy distance]).
Flash with Cleanse can get you out of any gank, just Cleanse go near a wall, click Q Ambush, Flash...
Be careful with Twisted Fate, if he is on the enemy team then I recommend you to pay EXTRA attention while backdooring.
They have Wards/Oracle's...
Well, what I do is (mid-game) if I understand they have wards, I buy oracle's myself and start to destroy their wards in a couple seconds its done. Just be careful and dont do it when they're all missing.
Still in lanes: just focus on him with your teamlane make an attack, go back, attack, go back...
Teamfights: Ask your team mates to focus on him, after 2-3 deaths he'll stop wasting money on oracles. They'll do it, since at this time you're the most important fighter in teamfights.
Note: The game will probably finish on your second PD, if not, then you will win the game easily if you know how to position on teamfights. If you don't win is because YOUR TEAM was really really bad.
Note2: Just ignore the noobs when they say "ks!" or when they say "why you dont help me?" (Don't EVER try to do a 1x2, 1x3 if you're not sure you have enough skills to do it, You're very good IF you don't keep dieing)
Note3: Don't try to kill before knowing if your lane mate is capable of helping you, if you get a bad lane mate that means an awful game for you :\
A game (ranked) where I had to opportunity to finish the build:
332k damage dealt.
Just a little show (not that BIG RESULT) but it's kinda how I play.
I'm new to twitch for like 1-2 weeks and I've learned a lot reading other guides.