try not to "over-prune". Limit pruning to end of march/beginning of
april to to allow limbs to heal properly. pruning in the fall makes
the tree susceptible to disease or fungus as it does not allow the tree
to "scab over" before the winter. look for crossing branches and
"suckers" that are only taking needed energy from branches that will be
most productive bearers of blossoms. make cuts @ 1/2" from the trunk
or leader limbs (not flush as it is easier to heal a lesser surface
area)

hope this helps!