pick a keyword thats only around 1000 hits a month and doesnt have alot of search results when you go to google, 30 million results, dont use that keyword, you wont compete
doesnt matter if you know anything about the subject, you can rank with 3 or 4 optimized articles, research the subject or pay for articles, rewrite other articles yourself
you can have 3 or 4 simple blogs, or just one, get some good affiliates and/or a store
think against the norm
keyword - doofus brain - 173,000 search results
pick anything, they are easier to rank and nobody is looking for them that much, its your market. youre here to make money and not get your jollys off writing articles on blogs that people, be realistic, are never gonna see in ten years on a google search
its like going to school, do the keyword research about something thats almost bizarre and noones writing about
you have to do your homework and learn about something thats foreign to you, put the time in and you can rank with just a few articles
noone is gonna see what you are interested in