I tell my clients to think of their websites like a sales funnel. Try to look at each step of the site as a step in the funnel. You want to shorten that as much as possible but still give your potential customers the information they need to make the informed decision you want them to make.

Secondly, you want to test, test, test. There is no silver bullet here. By setting up an A/B test process on each of your pages and on each element of the page, you can test every aspect over time and optimize to get the best results for your website. There are some really easy ways to do this now. So, whatever you start with, do the testing and improve it regularly. Make testing, evaluating and improving an ongoing part of the process and you will get the conversions you want.
Enjoy!