Q: Spear Shot
Great for finishing off people during ganks because it can crit. It scales extremely well with AD, which is why I run Flat AD runes rather than ArPen. Max this first. Does not apply on hit effects (red buff).
E: Heartseeker Strike
Late game this does TONS of damage if you aren't behind. However, early game, autoattacks are more important then taking the .75 seconds to cast this because it is very weak.