You did not mention what type boat you have but its true that there are some boats that do better then others on the ratings. Its also true you can take a really good skipper and crew on that poor rated boat and they can make her look really good. You can take an average boat and race her well and get in the middle of the pack, maybe even take a third place occansionally but if you want first it takes the right boat and crew.
I enjoy racing and you can learn so much about your boat and yourself in such a short amount of time. Its especially benificial to grab skippers from other boats that know what they are doing and get them to sail on your boat and you do the same on theirs. I consider myself a newbie to racing but if I had to offer advive to someone just getting into it I would reccomend a clean bottom, telltales on mainsail and jibs at the correct places, learn and know the rules of racing, and learn how to get a good start....Oh another one is steer on the low side and keep those telltales streaming strait back at all times.