I've sold each of my three boats pretty quickly by using a simple ad like this:
What I recommend is:
Take all your crap out so people can see the condition of everything, including the storage compartments.
Upload as many pictures as the site will let you. I cant help but think something is wrong when people upload an odd single pic of the boat or interior. Show enough confidence in your boat by adding a complete representation of your boat. It won't leave people guessing.
Take purposefull pictures. Congrats that your GF has big hooters, how is that relevant to a sale? See comment above.
Do your research first and know the market. Price accordingly.
Use a ton of keywords in your ad. Anytime someone is searching for brand X yours will come up too.
Don't be afraid to pay a few buck to list in the right area. Two of my boats sold quickly using onlyinboards.com and the one above just sold on CL.