You are to go into lane until level 6 then NEVER leave spawn...EVER. You sit there spaming your abilities for tear of the goddess and archeangle's until you have max stacks on it and when you can get a kill or assist in one you ult.

Magic Pen for the damage and gold for the extra needed income.

Keep Kage's Lucky Pick for gold, get that Cooldown reduction, and AP items for the damage. Throw in a philosopher's stone anywhere if you feel lacking in gold.

Promote a minion to mid every time you can and surge before every ult.