Start

Doran blade
I start with this item because Doran gives more hp and basic dmg. It helps a lot when we are at lvl 2 (watch Example Tactic) If You wanna use this as start item you need to know how to doodge enemy skills. (You are slower without boots)

3x Hp potion and Boots of speed
Good start if you wanna be a little faster, and if you need to avoid enemy ranged skills attack.(I usualy don't use that.)

First back to base

Boots of mobility
Good choice if you can't win your lane (agains champions like Mordekaiser, Swain) and go make some gangs.

Boots of Speed + Ruby Crystal + Doran Blade
Take this items when You have trouble in your lane and u can't help other lanes (for example all of lanes are pushed)

Boots of Speed + B.F Sword
Take it if u dont have trouble with your opponent and he dont buy armor.

Boots of speed + The Brutalizer
Take it if your opponent bought armor items.

Core

Bots of mobility + Frozen Malet + The Black Cleaver + The Bloodthirster
Main core of build, you should have all of these. (If somone dont know why i chose frozen malet, I take it becouse he give us a lot of hp and we can slow the enemy)

Situational

Ravenous Hydra
Hydra's splash damage is good to farm as well.

The Bloodthirster
We making this items when we don't have trouble with survive and we want to do more damage, heal a little every damage.

Guardian Angel
(When we need more defense)

Last Whisper
When enemy bought a lot of armor

Quints
Flat Attack Damage

Increases your damage and is required on an AD caster
Armor Penetration was nerfed in Season 3 and isn't as strong as flat AD
Helps your last hitting


Marks
Flat Attack Damage

Increases your damage and is required on an AD caster
Armor Penetration was nerfed in Season 3 and isn't as strong as flat AD
Helps your last hitting


Glyphs
Flat Magic Resist

You have to take this against AP mids
Even if you're against AD mids this is a viable choice if they have other AP on the team
If the jungler and mid laner are both AD I would instead take Magic Resist Per Level Glyphs


Seals
Flat Armor

You have to take this against AD mids
Even if you're against AP mids this is a viable choice as they will have other AD on the team
Helps reduce damage from auto attacks, which is a main source of damage early game.

Offense

You put 21 points in offense to increase your physical damage

Defense

You take 9 points in deffense to incrase your health,magic resist, armor. That will help you stay alive.

Flash - gives you the mobility needed to escape, catch people, and outplay your opponent.

Ignite - increases your damage, allows you to secure kills, and the healing reduction is strong against opponents such as

E is very good agains squishy (in early game) champions like Ryze,Katarina,Syndra,Ahri,Cassiopeia. Just wait for 2 level, jump on enemy (when he waste skills)with yours E, use W for slow, damage and finish him with yours regular atack. However dont run when he will attack you with auto attack. Remember yours auto attack is better. That tactice give you first blood.


If somone want know more abaut tactice watch that video:
http://www.youtube.com/watch?v=znsOcAfeWfs

http://www.lolking.net/guides/91579

Specially thanks for my friend Martinael who correct my wrongs.