Pepper Trees get huge - if you are pruning to maintain size, its hopeless. Otherwise, the only pruning that needs to be done is rubbing (or cutting if they are larger) off any branches that are too low. Cut out any branches that cross through the center of the tree. When the tree is larger and the branchletes start hanging too low, you can cut them up but its a constant battle as Pepper Trees really want to sweep the ground with their long graceful branches. I love them!
BTW: They are very brittle and large branches periodically break in the wind. Don't plant to close to your house or over your car port.