Hi Jeremy, and welcome! You can find a collection of tips and advice on the following thread: https://www.secretshopforum.com/thread/1/2/94/pro-tips-for-those-who-want-to-be-the-best-shoppers#post528
Additionally, going to the www.iSSprep.com website and completing the iSS 101, 102 and 103 courses (which are completely free and don't take long to do) is a good way to start and learn a lot early on.
As for making money - yes, there are people who use mystery shopping as their primary source of income, as well as people who only do a shop or two from time to time - it all depends on the availability of shops in your area, and your willingness to do them. I found a discussion about income from shopping on the following thread, I hope you find it useful: https://www.secretshopforum.com/thread/1/1/630/do-you-make-money#post3621
I hope this helps!