You can also look for products on affiliate networks which you can promote which relate to you blog. How much traffic are you getting?
I think you should sign up for Google AdSense. That will allow you to put ads on your blog. When somebody clicks an ad in your blog - you get paid. Register for an account at clickbank. Look for articles related to SEO. There are thousands of them! That'll make you a bit richer.
I think You should add advertise to your blog. You can sign up for different advertising networks like Google Adsense, Adbrite, Chitika. You can also sign up for affiliates of different sites and put their affilaite banner in your blog
Here are a few. CPM ads Smowtion AdsDaq SpeedyCPM VAdvertisement PPC Adsense Adbrite Adtoll Clicksor Inline ads Kontera Linkworth