Aside from google adsense, you can also apply for google afilliate marketing for added dollar earning possibilities. You just have to go to google afilliate marketing and apply for it. In my case, it only takes a day for my application to be approved. Once your application is approved, you will have your own afilliate marketing account and from your own account, there are many companies afilliated to google, which you can choose from. Of course, you have to choose the company with products that has something to do with your niche blog. And when you are already an afilliate marketer of products from the companies you have chosen, you can now display their ads (banner, image, texts and links) into your blog. Just get their ads link codes and copy paste it into a particular place of your blog, where you want to appear.