Setting up a goal in Google Analytics is the first step toward creating a well-designed online conversion funnel. The information you gather will show you where your users are leaving the conversion funnel. You can either use a Goal Template or a Smart Goal, or you can design your own.
You might notice that visitors are bouncing off of one page in the conversion path, for example. Then you realize that the price is displayed on this page. Is it possible to increase conversions by pushing the price down the sales funnel? Would it be beneficial to include trust aspects on that page? These kinds of questions will help you improve your funnel and eventually increase conversions.