Greater Seal of Defense Gives you the armor you will need and are really good in the beginning of the Game !

Greater Mark of Desolation And Greater Quintessence of Desolation Are very good with your Demacian Justice And Judgment to get the MAX Dmg out of it

Greater Glyph of Magic Resist Are very good because you dont have to mastery "Resistance".

Mercury's Treads for Tenacity and Some extra Magic resistance

Youmuu's Ghostblade Is Good For The Armor Penetration you have and matches With your Armor Pen Runes, (Also gives A good Escape Spell)

Infinity Edge Makes Your Crits Go BANG and Your DMG rises.

Frozen Mallet Will Give you some Extra Health And Good Slow

Last Whisper Gives Extra Armor Pen wich also will help you!

Warmog's Armor Will Give you Some Hp That Could be good if you wanted to Towerdive Someone!

Because your Decisive Strike And Your Youmuu's Ghostblade Gives you Movement Speed You wont really need Ghost So pick Flash Instead.

Ignite isnt really something you will need as garen when you have your Demacian Justice so take Exhaust to slow enemies and pick up the kill with your Ulti. :)

Well The Masteries Is Kinda Easy to tell what im aiming for:

Veteran's Scars Vigor For some Health And Regain

Then i go Summoner's Wrath For the Exhaust Buff And Weapon Expertise For The 10% Armor Pen It goes Well together With Greater Mark of Desolation And Greater Quintessence of Desolation And Your Judgment And Decisive Strike to Get some Extra Damage.