Some people will tell you that juggling is all about making
good throws. When you think about it, this is obviously a
bit silly. Juggling is about throwing and catching, and you
can't juggle unless you can do both. To juggle larger numbers
of balls, or to do more complex tricks, you have to be able
to do both pretty well.
If you're really good at throwing, you can get away with
not being so good at catching, and vice versa, but it obviously
helps to be pretty competent at both.
Some tips for better catching :
Open your hand wide to give the ball a large target area
Mentally visualise where the ball is going by watching
its arc, so you can get your hand in the way.
Wait for the ball to come down (gravity has to date proved
quite reliable in this area), it will. By reaching up and
grabbing the ball before it comes down to waist height,
you're giving yourself less time to concentrate on your
throws. Relax .... I promise it will come down.
Finally, don't try too hard, your subconscious will work
it out given enough practice.