There are a couple different patterns for juggling with one hand, and they can be important for tricks, and with 2 hands as well.

Inside Shower pattern- This is used for the traditional method of juggling a fountain. The ball is thrown from near the middle of your body, then curves outward slightly, then it is caught on the outside of your body, it gets caught, then you scoop it back to the middle, and throw it agian.

Outside Shower Pattern- The opposite of the inside shower pattern, the ball is thrown from the outside and caught ont he inside, thast all there is to it.

Columns- The balls are thrown straight upward, they never cross paths. your hand moves to go under each ball, as it gets thrown, then you repeat the process...etc This pattern gets really hard with 3+ balls in one hnad, you have to build if a lot of speed to do it.