Hi :) , i want show you my build (no tactic cause its secret xD xD )
Ehm, sorry for my english but we are only peoples and nobody is perfect :)
This is my first build because i am lazy to write it here...

Why this masteries?
I try too much masteries but in my humble opinion this is best (all what i need)

We can have 6 items, so if you realy look at my build i show you only 5 base items
1. boots
2. Youmuu's Ghostblade
3. The Bloodthirster
4. Trinity force
5. Warmog's Armor
6. ??? -> It depends on game... you can buy infinity edge and than bloodthirster or phantom dancer for speed and att speed or some armor...

I think everyone know : Start items are based on enemy...
I usualy start with dorans bladebut if you have ad enemy on line it is better start with dorans shield
What about boots?
i usualy build this cause i dont build another att speed ( only in trinity force) but if enemy have too much slows or stuns and you are not good for avoid it you must buy

- Good item, somebody build only Brutalizer, but i have it for active skill in this weapon...
You can get more damage than infinity edge and wamp will help you spend more time on line.
Awsome item can be changed for infinity edge but i prefer this for UNIQUE Passive: 25% chance on hit to slow the target by 35% for 2.5 seconds; on cast, your next attack deals bonus damage equal to 150% of your base attack.

You must know your hero.. your damage what you can deal or what you can get...

I have 2 types of combo..
btw always when i use E and know its last combo for kill i use youmuus-ghostblade active skill
1. vs mages (realy easy)
use E (for silence and jump) than Q for hit and W for slow (when i deal slow i run out) enemy will have something about half hp (+-) i wait for reause E than i jump again (so silence) than Q for nice shot and bleeding fast R (double click = blades from you and blades into you = 260(+bonus) + 260(+bonus) dmg ) if enemy still alive you can use W and Q

2. use E (for silence and jump) than Q for hit and W for slow (when i deal slow i run out) enemy will have something about half hp (+-) i wait for reause E than i jump again (so silence) than Q for nice shot and bleeding and R (blades from you it give you speed so i run with my enemy and when Q reuse i use it (nice shot with bleeding and ultimate skill will active (blades into me)

Sometimes you use skills on situation... i cant say what to use because it depent on teams

I dont know if this build is correctly written but i want know your opinion...

Thank you for your votes and opinions...