ComDriver, it divers a lot from site to site. Key elements for a good (money making) website is good content (information/an online service/photos&videos, etc.). A good domain (easy to remember and spread around). A fixed target audience and a nice pay model. Usually it's important to get an audience first. If you're able to build up a community of any kind, you can let them suggest how to improve your site. Once they are "hooked" you might think of introducing "extra" services (paid).
The trouble with setting up a site where visitors have to pay in an early stage is that if the site looks succesfull, there are always people wiling to copy the site and still offer the content for free, making you loose your audience.
Do you have any ideas in mind. Themes/audience/kind of website?