How do I begin?
 

I have a 85 735i which has sat up for over three years, how do I begin bringing it back to it's former glory, without messing it up!!

Larry

change all fluids and filters, belts and a new battery and you should be good to go.
while you are at it have the tires checked just to be sure.

I'm doing the same with a 1990 735i. It was started and driven shortly approximately every two months over the last 3 years. Where are the fuel filters located ( in case there is more than one )? Any tricks to bleeding the fuel system. I just heard it run and idle so there is hope. This is my first BMW so I'd appreciate any advice.