"Is it a solid approach to literally just create dozens of separate blogs and post banners of the product you are marketing?"
That's a shot gun approach that will wear a newbie down before they make a dime. Pick one thing, do it well. Get traffic. Make sales. Then maybe add a 2nd or 3rd.
Granted a pro could do 12 blogs on 12 subjects if they wanted after they had LOTS of experience. But even James Martell who is one of the top gurus in the industry posted here saying if he could start over what he would do differently is to put all his energy into one niche and one site instead of being spread thin.
"What should you put on your blog, how much should it contain, specically what should you do in order to get people to your site?"
The answers would vary based on a whole lot of factors. Best thing for starters is to read other blogs in that niche and see what types of topics they write about. Go to
Technorati: Home and search by keyword or by tag to find other blogs in your niche.