As you know, one of our specialties is flipping homes for our customers so they get top value when selling. There are some do's and don'ts. Go for anything to do with the homes appearance, landscaping, painting, wallpaper removal, hardwood floors, interior doors, baseboards, crown moldings, new lighting fixtures. These upgrades are relatively low cost but high visability.
The don'ts are things that are high cost but low visability. You will not get a good return on the money spent. These would be, roofs, heating systems, electrical, plumbing, driveway replacement, pools (which some folks like and some don't-but generally doesn't add value. Obviously, if there's a safety issue you should address these things, but not necessarily for the sale. It's the high visibility items that bring in the Buyers.