If you join the clickbank then it is upto you to choose products you are going to promote.
The products have to be in good demand.
This can be found if you know how many people look for it in the internet.
The search engines have databases that store the searches made by millions of people everyday.
There are ways to get these data and they can be expensive. Still for beginners and learners a free trial at
http://www.wordtracker.com/ can be of help.
knowing the things people search (words people use for searching the items) one can advertise in their
blogs, websites, or newsletters. Or use google advertising.
Find out what people buy in the internet.
Until for the next post.
Sean