Hold one side in an isometric contraction while the other arm moves through a dynamic (concentric and eccentric) movement. You then switch sides.
This simple modification not only helps you to create a new training stimulus, it also creates muscular overload by increasing the time under tension (TUT). By increasing TUT, you increase metabolic stress, a key mechanisms for growth.
Instead of my usual Q & A column this month, I'm going to get a few things off my chest. Don't worry though, it won't simply be the ranting of a dieting bodybuilder; you'll probably learn a few helpful things along the way, too!