Make less mistakes than every one else.

This is a strong mantra to use to start with. Get your boat speed up with the front runners first. One duff tack will loose you 50-100m on the course. Next time out count the number of duff tacks you make, add in the number of duff gybes and multipy by 50m. How far infront of you is the leader ? I'd wager it is less than duff tacks + duff Gybes (and Spi drops/hoists if applicable) X 50m.

Also, get to the championship venue early so you can get some "local" knowledge.