Hello.
I all depends on whether you're talking about a show car or a car to drive. If it's a car to drive, you would want to address all the safety issues first, like brakes, steering, suspension, etc.. then get the body solid by repairing any rust it might have, then you would want to sort out all of the electrical glitches before you paint the car, because electrical problems frequently call for some disassembly.
If you have specific questions, I'm sure that someone here will be able to help you out.
