Lindsey,
Limbing up branches on a tree is a personal prefrenece, it will also depend upon the species of the tree. Some tree habits look best with branches sweeping to the ground. Street trees and trees near sidewalk are usually limbed up so one can walk underneath with out injury. This could be as high as 12 feet.

Thinning is removing interior branches or small lateral branches to let in light for better growth. Again, it will depend upon the age of your tree, what species is it, and what are you trying to accomplish.

Start slow and remove a few branches at a time, step back and see what the tree looks like before removing more. Remember, you can cut it off, but you can’t put it back on!