I give the one I've written up away, & plan to do the same with the rest.
But...here are my opinions for anyone who would like to sell adventures:
1. The most important thing to realize (as several threads here on ENWorld have made abundantly clear) is that different people want different things from adventures. There is no single formula for the contents of an adventure that will sell to everyone. You need variety. You need to clearly communicate the differences between different styles of adventures so that customer A will understand that adventures I, J, & K will give him the kind of contents he's looking for while adventures X, Y, & Z probably won't be to his liking. While customer B will understand that X, Y, & Z are the style he likes, but I, J, & K aren't.
This, however, is going to take some hard work.
2. Instead of focusing on getting as much as possible on each page (because modules don't make money), focus on making the module as easy to use as possible. Try to come up with innovative layouts & techniques that will make the DM's job easier. Thus, you will add value to your product & customers will not only buy them, but be willing to pay a premium.