I agree with all the advise given, and will also offer to do a tutorial on my trees if you are closer to Woodinville than Enumanimalsex.

A really quick and dirty method is to cut off all limbs going straight up, all limbs growing in toward the center of the tree and all limbs that cross another. Then whack off the dead limbs and you are in pretty good shape. If it's an old tree you can expect a ton of suckers the year after the first heavy pruning.