The obvious..........when taking things apart keep the nuts and bolts together for each individual part in a separate container/baggie. When I take a piece of metal off I like to hang it, doors, hood, fenders. I hang it to keep it off the floor so it doesnt get damaged, because it will.
Dont throw anything away, regardless of condition. You do not know if you will be able to replace it or you may need something to compare a new part to.
Did I mention to take a lot of photos.........Not just for us, but for reference.... Many of those parts have part numbers on them.