Pedal in circles.

The problem with poor pedaling technique is that you work against yourself ... essentially applying pressure to both the left and right pedals at the same time. I know that if I focus on trying to apply pressure on the other foot in the upwards direction, I may not be generating much torque (if any) with that foot, but at least I'm not pressing down on it.

Focus on it the next time you're on a climb, and you'll find yourself magically picking up a MPH or so ... with seemingly no additional effort.