This one tip revolutionized how I play bot lane. It's simple, but effective.
I'm gonna sound like such an idiot for not learning about this until two days ago, but here we go.
Aim your spell at an enemy when they are attacking a creep. All AA animations force you to stand still and be unable to do anything for a fraction of a second. When you see an allied creep that is low health and the enemy is going to try attacking it, fire your spell at them when they start the animation.
They now have to choose between A) Canceling the auto really quickly and missing the creep and B) Taking the harass.
It is incredibly simple and once you get the hang of it, you will land so many more skillshots.
GL on the rift.
lol