This is a tough job because Racket's macro system is at the edge of the known, so there isn't a great deal of material about how to use it. There are a few guides around, particularly for the older syntax-rules and syntax-case, but for the latest and greatest the manuals and the research papers are the best source of information.

A good guide to start out with Racket's macro system is Greg Hendershott's excellent Fear of Macros tutorial: http://www.greghendershott.com/fear-of-macros/