I'm not modding, I'm improving
Re: how to avoid swirl marks
Can't really add to jimmeh's link, but you are likely to have holograms and buffer marks from the bodyshop's respray. Best advice I can impart is find a local "nice" detailer who will detail the car's paint work, but teach you to care for it properly and show you how to detail the rest of the car such as plastics, glass and metals.
A lot of my clients last year came to me having bought a machine polisher but with no clue on how to use it. They sold them, asked me for paint correction services but still wanted to do a lot themselves. Something I had no issue with as my detailing was a hobby more than a business. I made sure they knew the basics and a little more!