Getting people to buy into your ideas or buy your stuff is marketing. It is psychology. It is done with WORDS.
The first-most important factor on a website is it's headline. This is what people see right away. It has to get attention, and raise curiosity.
Crafting a good headline takes many hours. Crafting a great headline can take days or weeks.
The second-most important factor on a website is it's offer. What's in it for the visitor? Why should they buy? What do they get?
The best offers are usually developed over time, with lots of testing. Try different offers and see which ones bring in the most business.
The third-most important factor on a website is the call to action. People need to be enticed into doing something.