Don't be afraid to charge for rush work
Among the many focuses I had as a new freelance designer, one of the big things that I was always concerned about was client satisfaction. I never wanted to drop the ball or give clients reason to fire me, or worse, not want to work with me again. As a result, if a client came to me with a rush project, I was apprehensive to charge a rush rate. I'd charge my normal rate under the guise that it was good karma... or something like that.