I remember reading once, though I can't remember where, about a technique called 'contrasting'. The idea is to visualize a world where you've accomplished your goals, and visualize the current world, and hold the two worlds in contrast to each other. Apparently there was a study about this; the experimental 'contrasting' group was more successful than the control in accomplishing its goals.

It's called mental contrasting. The relevant studies are cited in the optimizing optimism section of How to Beat Procrastination.