I had experience of about 1 year. But past one year went in RND. Now i started making from google adsense. from past one month visitor are increasing and so the earning. But it a big task you need take good look on your site SEO and quality backlinks.
I have over two years experience using adsense. I have learned much from experimenting and reading. I spent six months dedicated to learning everything I get my hands on about adsense. Now Im focusing on learning everything I can about link building.