Method for Starting a Project

Kinda depends what you're starting with.
If it's not much more than a bare shell or a roller, I'll start with all the stuff that I can't get at if it was a complete car- engine bay, suspension, hardlines, wiring, any floorpan/frame work. That kind of stuff. Then I add other things depending on what I already have on hand, and start the search for whatever else is needed; then move on as other parts are acquired.
I seem to approach things a little different than most people in that I save the driveline for last; whereas most people seem to build their engine/trans first and finish the car around it. I can't do that- it makes no sense to me to build a fresh engine and then leave it sit, possibly for years, while the rest of the car takes shape (and possibly life forcing you to put things on hold entirely).
If it's a complete car, I start with whatever it needs to make it driveable and safe. Then move on to what I want to change, if anything.