I'm eager to learn about conversions, and the best way to do it (I believe) is thru learning from others who have done it successfully.
One of the most significant results I've seen was for a client of mine - Switch Video. We changed one word on their call to action button and increased leads generated by 228%. How'd we do it, you ask? Well, first we surveyed their customers to find out what questions they had, and then we made an educated changed based on the survey results. It always helps to start with research so you're not just guessing about what to test.