And now, the most important part (for advanced players only):
First try juggling while you ride around town. The worst part of juggling while on a unicycle is that when you drop a ball (or hit a pothole) you have to stop, get off the unicycle, pick up any lost balls and get started again. But once you've got it under control, try juggling those jumbo neon-colored superballs you can find in any toy store these days. Juggling those while riding on a flat surface, you can "accidentally" drop a ball, CATCH IT ON THE REBOUND, and resume juggling!
Oh, and remember to look both ways before crossing the street... You'd be amazed at how fast those little balls take off when they hit a rock, and how hard it is to catch up with them. Hazards of the trade. :-(