There's a great article that expands on the following ways to earn profits from a Blog. It's quite useful and very complete.

CPC Ad Networks

CPM Ad Networks

Affiliate Product Sales

Direct Ad Sales

Ads, whether private ad deals or through an ad network, remains as the most poplar form of blog monetization. However, there are a lot of successful bloggers that move beyond this. Some of the ways that you can make money off your blog other than ads are:

• Events Information Products
• Consulting, Coaching, etc.
• Services related to their topics (landscaping services by a landscaping blogger)