They usually need little pruning, except for height control, or if a branch leans over too far. If it's too tall, follow the tallest branches down to the base, and cut them there. Don't remove more than 1/4 of the foliage at a time. The same can be done with leaning branches. New shoots should appear from the base to replace the ones that were removed. The best time to do this is in early spring, so soon, if not now.