Carnuba content is the key. Mother's and Maguires are the best products I have used. They have high Carnube content the down side is Carnuba is very soft wax and doesn't withstnd soap and water very long.
Rain-Ex comes in a yellow squeeze bottle and is used on glass to make water bead up and roll off.
I think it's important to rinse and pressure hose dust and dirt deposits off the body before you use your wool mit to wipe with soap. Dust and dirt remaining on the car body while wiping is abraisive and eventually dulls the finish.
Using a cleaner wax occasionally will reduce the small scratches that cumulatively dull the finish.
These are things I have found to be helpful.
Bill George