Yes of course you can!
Blogging is a great way of earning money online.
You need to be regularly adding valuable content to your blog. Driving a steady flow of traffic. Forum sigs, blog commenting, guest blogging, social media, SEO etc.
Monetize your blog with affiliate products in the shape of banners, links, product reviews, 'recommended tools' page. You can also build an email list to retarget subscribers into returning to your blog to read your new content or send affiliate promotions direct to them.
If you are getting a lot of traffic then you could sell adspace to.