I usually ask that my players supply either a short backstory (no more than 200 words) or complete a short character quiz that answers some key details (where do they come from, why are they their primary class, are they a leader or a follower, etc.). This is to be supplied by the end of the third session their character is in, to give them time to find their character through play. If they are having trouble with it I'll help them come up with something suitable.
So far it's worked quite well - enough information to give me some hooks for them but not so much that I have to agonise over how to fit their character into the ongoing campaign.
So far it's worked quite well - enough information to give me some hooks for them but not so much that I have to agonise over how to fit their character into the ongoing campaign.