In my world, all prospective client opportunities go into a sales pipeline where they can be tracked and monitored. This is the biggest way to impact your bottom line - really tracking those opportunities. I use a web-based pipeline program but you can use a whiteboard - just track the stages of an opportunity from initial sales activity all the way through to referral customer. More on this later.
For now think of just one opportunity that you are stuck on. Why has it not come to closure? Have you truly qualified the opportunity, because if so, most properly qualified opportunities will close. The confusion most people have is in knowing what is truly qualified. Rethink the opportunity - walk it through, find out what you are missing. Ask a successful seller that you know - not necessarily in your industry - to hear you describe the opportunity and ask them what is missing.
This works for other sales activities too - I have a colleague who has toiled over not revising a sales letter her business associate asked her to revise - it has been weeks, and she feels bad plus it never got done. I asked her two questions and now it's getting done. One of the questions was, "Can someone else do this for you?"
Bottom line: figure out what needs to happen, then move on to the next opportunity. Being stuck slows you down, sometimes to a halt.