I keep a post in my character's journal that's just a massive infodump of everything he's learned in the game so far along with links to posts that are particularly relevant to him.

And I can't second the "read everything" enough. Making little mistakes like asking a question that's already been answered isn't bad if it's only once in a while, but if you're constantly making fumbles like that, it's going to make your character look incompetent.