There are not enough hours in the week for me and sometimes I concern myself more with stats and earnings and not so much what I sell. I made an effort late last night to go over the huge reports of products I have sold, and uncovered 3 very untapped niches with a wealth of untapped keyword phrases and exact domain name matches unregistered as well. These sites will all get a quick install this weekend of the Keywords To Websites plugin I talked about in my top 40 Wordpress plugins post until I can get back around to giving them content and converting them into full fledged review/product niche sites. I have 100% confidence these will do splendid right out of the box and even better when I get them built to their final stage.
I highly suggest looking over your sold reports in Amazon, EPN and whatever other affiliate program you belong to that lets you see what you sold. If you are new to the business, but do not sell much currently, pick a day and just surf aimlessly through Amazon and eBay. Make notes for about 30 or so different items and then do your research. Do not pre-judge anything, let the research tell you the good or bad. Your own stats and numbers have so much information that we often ignore.