I recommend getting and reading Dave Perry's book explaining the R-O-W rules: "Understanding the Racing Rules of Sailing 2009-2012". Obviously it would be a good idea to wait just a little bit longer and buy the new version which will be out soon. There are other books that explain the rules (The Rules in Practice 2009 - 2012 by Bryan Willis, for example) - I have both but I prefer Dave's. There are several good rules blogs such as this one that lists the ISAF Rules study guide among lots of other good info: http://www.unrulyracing.com/2012/09/rrs-2013-16-study-edition.html

As I wrote earlier, it has never been easier to get good rules info and study material, quizzes, videos, etc. Just spend a little time looking around and checking it out to see what most appeals to you and your learning style. There is even an app to load the rules on your phone so that you have them with you wherever you go. One of my favorite ways to better understand the rules is to read the US Sailing and ISAF rules cases which are also available online at: http://raceadmin.ussailing.org/Rules.htm