I find I have to force myself to only look at, think about and work on smaller goals and not the big picture. There's just too much to try to take it all in at once. When I start to get burned out I shift gears to another project/different hobby (bad idea) that only takes more time and money away from the car I really wanted to get done. I sold off one of the projects I was never going to get to, now down to 3.