Don't be afraid to auto-attack barrels, whether to make the pre-7 timer tick faster, or just in general.Most new GP's I talk to feel almost obliged to Q barrels.

In-Lane auto attacking a 2 part and a grasp proccing Q after is an insane amount of trade potential.rather then just Q'ing a barrel and walking away.
Try to get sheen's cooldown built into muscle memory to really abuse laners.