This came up with a discussion I had with my son after a game session one day recently. "How does someone "train" to play the game better?"
My answer to him was, "read more books."
Really, that's about the best advice I can give to any Player of AD&D. Read, read and read some more. I would suggest to stick more on Fantasy and Science Fiction but even some good mythology and history are able to help.
Philosophy and world religion are also good subjects to read as well. Even if they don't fit into your own personal thought and beliefs, knowing about how they work can help you apply them to PC's you create who aren't just avatars of yourself.
We can learn tactics, methods of negotiation, rules of engagement and all kinds of other cool stuff from these kinds of books.