Bob - A picture would help considerably.

As stated "damaged, dead or crossing and rubbing on each other" and also growing back to the center of the tree. I also remove or pull down vertical growing branches.

As for the height of the tree. Don't remove more than 30% of the tree in any one year. Peach trees generally like to grow more horizontally than other fruits. Trimming or pulling down young vertical growth helps the tree grow horizontally. You can pull down young growth with paperclips and big washers on twine. I also tie off twine to the fencing that the deer here make mandatory. After a few months you can remove those tie downs or move them so that they are shaping the new growth on the same branch.