The guidelines for pruning almost all types of bushes are basically the same:
First, prune judiciously when the plant is getting ready to flower. Don't take off the prime growing tips! But beyond that, these are parts you can take off:

-Low growth that is weak and gets no light
-Growth crowding the center of the plant- as long as it does not support a primary growing tip- leave those be
- The weaker of any pair of branches when a pair is crossing or rubbing. If both support a primary tip, just try to spread them apart as best you can.

Do all your pruning ASAP, because it's just about flower time, babee!