Take 2 spheres and hold them comfortably in your hand
When you feel comfortable just holding them then move them to another position in the hand
Move them again....
Imagine at least 4 different positions of the spheres, and then break it down even smaller
Think of 8 different points around your hand for the spheres to sit.
Spin the spheres slowly but smoothly, be careful not to click them together
As the common Contact Jugglers saying goes..."Every click is a mistake"
Some last pieces of advice, stretch before doing any contact juggling, especially multi-ball,
Keep it slow, remember, every click is a mistake.
Try to grip the spheres less and open up the fingers to better show an audience what you are doing
Practice in both hand, both directions it'll pay off in the long run.