Back when I started airbrushing in the late seventies, there was very little information on airbrush techniques. Badger had a small thin book out that showed a few step by steps, but it was limited. I pretty much had to teach myself back then. Today, with the Internet information is at your finger tips. You can check out you tube for for some great how to's and you can watch other artist from all over the country work on projects. Here is a resource to check out.
http://www.howtoairbrush.com/