I am guessing you are asking about what kind of training or exercize you can do on land to help?
In my opinion you should build up your stomach muscles as well as pulling muscles such as the arms and lattisimus dorsi. So basically doing situps, push ups and pull ups regularly should help you.
It will not give you much advantage getting in the sailing team, etc. but once you are sailing it will help a lot in my opinion. Any cardio exercize won''t hurt either.
As for sailing itself, unfortunately in my opinion the only thing that will help you is to gain more experience by sailing more often.
Good luck!