What do I need to do/know to start a profitable blog?
patio11: You are not starting a blog, you're starting a business.  You need to figure out what niche that business is in, who are its customers, how it distinguishes itself from other competing businesses, etc.You will probably find that a "thin affiliate" site providing nothing but reviews of products which happen to pay you money does not provide people with an incentive to link to your site, join your community, revisit, or otherwise do things that produce long-term business value.