brajes, engine, etc. I like to first address body/exterior work so everytime I walk up to the car it brings a smile. Next, the interior is another thing I see and touch all the time. Last I move on to getting the engine compartment in shape and display worthy. It's under the hood so not as critical from a looks standpoint and it's nice project work in the off season.
Every car is different so priorities vary on what has to be tackled. Like any challenge breaking it down into smaller manageable pieces is key.