How to blog & make money blogging
John Hutson has put together a video on how to carry out research to find a great product worth promoting. Do this before you put your blog up so you can be clear about what you are going to promote. You can find John at http://www.twitter.com/johnhutson
When you are a blogger not everyone that visits your blog will buy first time. Give them a chance to get to know you and give yourself an opportunity to build an audience who will buy from you. You need to read the List Building For Bloggers eBook - Valuable reading for building your online income.