Look into the books (Cat sailing for the 90's, and another I forgot the name of...) Once you get comftorable with the raceing techniques you could looking into a new sail (Squaretop?) or adding a spin.

For Me... it was about 2 to 3 years of expereince and listinting to a local sailing on how to go faster. I will eventually get a square top and Spin for my 18 but till then I will stick with my stock sails and keep on learing.

Todd