[MalcolmDiggs]

If I've never worked with the client before I always ask for 50% up front. No exceptions. Once we have a relationship I may lower that, but it's not guaranteed.

Price yourself so that: if that 50% turns out to be the only money you ever receive from them, the job will still have been worth your time.

Keep your clients at arms-length. They are not your friends. Never allow the scope of a project to be changed based on a conversation or a phone call, anything that could get you sued needs to be in writing. Be very strict about this.