Gotta be careful is all
Make sure to only use products that won't scratch the paint. I have some microscratches on my finish, but they're not noticeable except in very specific lighting conditions. Basically, always use the right sponges, etc. I dry my car with a Cali Water Blade and then with a P21S Drying Towel. Then I touch up with Z-6 (my car is Zaino'd). Comes out perfect every time.
EDIT: I should note that the scratches I do have come from before I really got the hang of how to do it right.