Pre game is important for the rest of the game. for runes go Precision all of the options are good but i prefer Lethal Tempo since it gives me lethality and Magic Penetration. Then i go Triumph so in team fights im still alive and Bloodline so if i get fed i get seriously good life steal so i dont need to get Bloodthirster. for the next rune you get coup de grace for easier kills. And domination has an EXTREMELY important rune ill get to that. First pick Sudden impact so after you use "Q" you will get a sudden burst of lethality and Magic Resist hence getting more effective to destroy tanks. And the important rune: Ravenous hunter each first kill on an individual will give you life steal on your 1st and 3rd ability. For Summoner spells I go Smite Challenging since i need more damage to them and damage reduction to me. For 2nd one i always go ignite for a good early game invade. if its one person, he is dead! But if its 2 i ask for a leash.

This is your weakest point in the game but farm enough and you will get fed.