Excellent advice. Another tip. Read their back story. I know that sounds like 'well of course?' but no, seriously, read their back story and incorporate some elements. They're appreciate it and it'll help drive them onwards.

You know, I don't mean to be contrary, and reading back story is important, but I've always encouraged players to write as little back story as possible. Yes, it can inform the story of the game and should, but the story of the game should never be overshadowed by back story.