Hello everyone ! I'm Dzungla00 im an euw player.I'm curentlly sitting at silver V.My main role is adc. This is my second guide and i choose twitch because of his great damage output trough out the game.I will try to explain everything in this guide i hope you like it !
Also check out my Katarina guide : http://www.mobafire.com/league-of-legends/build/katarina-murders-ing-everyone-inspired-by-sawlicious-354991

+good damage output with e
+good duelist after you got Blade of the Ruined King
+ Ambush works like an escape ability and agresive ability
+ult helps you attack from far away when got focused

-one of the more squishy champs
-****ing killed in a sec by assasins
-doesnt have much cc rather then Blade of the Ruined King

Marks:
I take because it gives you a bit of damage and it's easier to farm with them.But also viable runes would be Greater Mark of Armor Penetration not a lot of people use them but they're actually awesome on adc's, it's your choice which marks

Seals:
I take because they will give you a little bit of survivability against the enemy adc. There really isn't any other viable runes for twitch.

Glyphs:
I take because they give you a bit of mr againts the enemy apc's

Quints:
I take Because they give you more ad,and the more ad you have the more stronger you are. But you can also take they will give you some lifesteal so you can get health back faster.

AmbushTwitch becomes invisible for a short duration,while invisible twitch gains movement speed.When leaving invisibility twitch gains attack speed for a short duration.
Venom CaskTwitch hurls a cask of venom that explodes in an area,slowing targets and applying deadly venom to the target
expungeAll nearby enemies secrete Twitch's toxic venom's from their bodies,dealing damage for each stack
Spray and PrayTwitch closes his eyes and fires from his crossbow,rapidly spraying powerful piercing bolts ahead of him

[ abilities=1 ]
I try to max my expunge because it's your primary damage ability and it will help you chasing enemies
Then we want to max our Ambush for that stealth
Then we want to max our Spray and Pray since it gives you range and more damage
Max your Venom Cask last since there's nothing left lol

Blade of the Ruined King is an amazing item on every adc's and im sad that people don't rush it. I Mean it gives you a slow and it works like a bloodthirster pls read the passive
Berserker's Greaves give you that movement speed and attack speed normal adc boots
Infinity Edge is a great item combined with Blade of the Ruined King you gotta buy it
Last Whisper gives you extra damage and armor shred because people will start building armor by now
blood thirster or Phantom Dancer it's up to you what do you want more :D
Guardian Angel, Warmog's Armor, bansee's veil by now the enemy will start to kill you so you want to take a bit of defense

This build is very viable for ranked play if you want. This build has won me many games and it's awesome in ranked.

I Made this chapter just to show the op Blade of the Ruined King
This item is good to rush when your wining your lane and when your loosing.It's a lot better to get it before any other item because of the big damage that it can put of and the cc that adc's lack of, plus it gives life steal,the less health you have the bigger the lifesteal is,so it's unreliable to take Infinity Edge before Blade of the Ruined King because IE doesn't give you life steal no attack speed,just damage and crit chance.But Blade of the Ruined King gives you attack speed which increase's how much damage you can deal plus it's passive. I dont know if you understood this but i hope you get the point :D

Thank you for reading my guide i hope you liked it and felt the power of the smelly rat.
Special thanks goes to jhoijhoi for her guide to making a guide: http://www.mobafire.com/league-of-legends/build/making-a-guide-101506
If you would like to play with me add me :). Remember im playing on euw