Originally Posted by GringottsVault711
After what was said in Book 6, I don't think he could ever master Occlumency. Legilemency -- maybe, but not if the two abilities are so closely tied together. In my fic, Harry is a Legilemens, but its helped along because his mother was one, and his ability is very crude and unfocused. He just randomly has insights into people's thoughts and has trouble focusing on what he wants to know. He tends to do it accidentally.
He did cast a quite effective spell against Snape, enabling to see into his mind, after all. But, I would stay away from Occlumency almost completely, unless you're planning on approaching it with a lot of development and recognising that Harry would have to have a VERY good reason to continue Occlumency, and he would have train extremely hard. His ability to control his thoughts and emotions is a huge part of him, and he would have to change to be able to grasp the skill of Occlumency.
Legilemency, not as big a problem, but something that should be saved only for the purpose of a plot in dire need.