Take care not to cut into old brown wood, since the plants will not produce new shoots from this. Shear to a few healthy leaves above the brown stems, and work systematically along the hedge, keeping it as level as possible.
A visual aide for pruning fruit trees at planting. Proper pruning makes for a stronger central leader (the trunk) and stronger scaffolding (side branches). And, on semi-dwarf and dwarf fruit trees, pruning leads to earlier production.