There are many things you can do to increase sales.

One of which is to not do what everyone else is doing. Some free traffic exchanges may convert sales for one person, and be a complete waste of time for another. If everyone were promoting GoogleCash in the same traffic exchange for example, then chances are pretty good you will not sell many GoogleCash ebooks. Don't get me wrong. GoogleCash by Chris Carpenter is a great ebook. I bought it while ago and it has some great information in it. But when people see the same ad over and over again, they get desensitized to it. Don't fall into this trap. It's one thing to try and sell a very popular product/service/ebook etc, but it's another thing when a million other people are trying to do it too. Competition is a good thing, because it validates your market, but too much competition is tough and it's time to move on to something else.

If you have your own website you're promoting, you are one step ahead of an affiliate marketer. If your website is what we call a "niche" site and has a big potential customer base, you are in a great position to generate very good income from your efforts. If you are in a very competitive market, then you are in for a difficulty and potentially very expensive ride. Stay away from hugely competitive markets unless you know what you're doing or your competition will eat you for lunch and leave you with empty pockets.