Armor Pen Reds
Crit chance Yellow
Magic Resist Blues
Armor Penetration Quintessences
Physical Attack masteries, Armor, Magic Res, and Regen based on mana pool for the extra HP5 early.
I play Blitz as a tanky dps champion.
Mana Saphire early, to build into Tear asap, which solves mana for the rest of the game. His power fist lets you last hit minions and does comparable damage to the grab at only 25 mana. Combined with lower cooldowns (down to 5 Seconds!) there's little reason to level the Grab early. The damage gain isn't wonderful, not compared to 2 pop ups, and its expensive mana wise.
You'll hit high base damage values very quickly. Pick up pieces of triforce and Banshee's Veil and you're doing a considerable amount of damage, are relatively tanky ( your manapool is ALWAYS near full), have a large amount of disrupts, and deal respectable burst and sustained damage.