I don't think the anger ever really goes away.

[ zuko has learned to slowly let it go, but he's far from well-adjusted. ]

But if learning is all you can do, then maybe that's where you should start. You have a goal, so work to achieve it. Other people will forgive you, or they won't. Either way, that's not in your control.

[ he learned the hard way, with katara, what demanding forgiveness when someone simply isn't ready does. ]