WR stick drills:

Homer Smith has the best drill tapes ive ever scene on this topic.

Basically what he has his players do when he was at UCLA was any time as the player was running if the WR coach yelled "stick" the very next step the WR had to stick his foot in the ground and balance on that one foot. Its really great stuff.

Another thing to tell your players is when they are "sticking it" to break is never take a long step. Because a long step into the break becomes a slow short step out of the break, have their stick it step shorter and you will see them explode out of the break.

Also whenever your WR's break make sure they never drop their hands below the belt, its a dead give away to the defender that he is breaking. Have them have active elbows at the top of their breaks!