When I first started affiliate marketing I started by creating niche sites, trying to get to the first page of google and promoting products with a very low commission rate. I saw that I was getting a lot more new visitors then returning visitors. I made some sales, but I was really marketing to the 2%.
I found email marketing which allows you to market to your list over and over as well as build a relationship with your list. I have seen better results with email marketing than I did with with any of my niche sites and I was also able to promote products/services with a much higher commission rate!