Make sure you line up the valve stem of the tube with the brand logo (or other identifiable unique spot) of the tire when you do your repairs. Then when you find the hole in your tube, it's easy to line it up to a spot on either the rim or the tire. Makes diagnosing flats infinitely easier. I've found a few things this way that I might have missed other ways.

If you already do this, then let this serve as general advice to others who might find it helpful.