Tuning it correctly
This is a direct link to Speed Sails Tuning Guide. How well it translates to other sail manufacturers, I don't know.
Crewing it well
Both helms and crews must work well in a boat to get it going fast. This guide from one of the top crews in the business, is well worth the 20 mins or so to read. It will let you know what you are doing right , and wrong.
Know the rules
Learn the rules by having a go at this interactive quiz. You need to register to get the solutions, but its well worth it. Having been registered for 6 months I have yet to knowingly receive junk mail.