Best way to avoid or minimise swirls or scratches while cleaning your car is to use multiple steps, this is what I do...
1) Jet wash the car down - removes loose dirt
2) Cover the car in snow foam and allow to sit for 10 mins - snow foam will remove smaller pieces of dirt, getting rid of (hopefully) everything that could potentially scratch it
3) Jet wash off the snow foam
4) Using a noodle mitt, wash your car by hand using the two bucket method (preferably a wax shampoo) - this will remove any dirt that is left and hopefully not cause swirls as per previous steps
5) Rinse, not jet wash, the car down
6) Leave to dry. Using anything to wipe it down is just more risk to swirls - you will get water marks but don't worry (another effective way to quickly remove water from a car without touching it is to use a leaf blower)
7) Clay bar the car - remove all the tiny, microscopic pieces of dirt and also the water marks
8) Wax/seal the paint work
9) Polish windows
10) Sit back and admire how god damn good your car looks!
This 10 step method has led to absolutely flawless paintwork (for me anyway) since i've owned the car. Yes you will ge the odd mark/scratch but waxing the car will hide these. If you do get big swirls, scratches, tar spots, get your car machine polished - or do it yourself (ONLY if you are confident and have experience. Unexperienced machine polishing will ruin your cars paintwork in a matter of seconds!)
I use Juicy Details (UK based) for all my shampoos, waxes, snow foam and even cloths and applicants. There are so many too choose from out there though.
This is a very time consuming process but for someone like myself, I love doing it. I would never let anyone else clean my car, trained or not. Detailing is a passion!!