Content is a king, you should add nice content and promote your site and you will be able to get more income
Have you experimented with a different layout? You know Blogger has an advanced design button to change your layout, colors, and width of your blog.. Maybe if you experiment with layouts and ads you may increase your earnings. Add more content and content on the side of the blog because from my experience most visitors pay attention to the side content of blogs or websites. Just a suggestion..