1 blog = 1 site If you want to have significant revenue streams online DO NOT stick to 1 site/blog. My 2 cents.
At times it works at times it doesnt - But my 2 cents.. dont experiment with too many things when u begin something.. learn and then experiment
IMO, using both methods is the best : focus on one make a lot of other blogs that link back to that one , on the same niche, but you need to know what you're doing here ~yoozy
You can try keeping 1 first. Then learn SEO, Adsense, and create backlinks with this one site. When you've already figured out how to do these, get another one... and another one... and another one. Just remember to keep on creating backlinks. Good PRs should increase your site's value.