1) Google AdSense: is essential if you are looking to make money online. You get paid based on two formats: CPM (cost per thousand page impressions) and PPC (pay per click). Google AdSense scans your page and places ads according to the content (FYI: real estate, jobs, cars, and personals ads generate the most revenue). It takes time to build consistent traffic, so don't be discouraged.
2) Google Analytics: a free tool which shows you how traffic gets to your page (referring websites, google keywords used), average time spent on your website, most visited pages, and a number of other useful stats. Surprisingly, my most popular blog postings are videos. Reno 911 - I Won the Lotto!" is my most popular link.
3) Amazon Associates: is Amazon.com's affiliate program. If I'm going to reference or promote a book, TV show, or movie, doesn't it make sense to make a commission off of sales? Typical commissions paid are 4%-6%.
4) AddThis: is the most underrated promotion tool (I'm upset that I didn't add it sooner). It allows you to add a "Share It" button so people can bookmark, email, Digg, Delicious, share via Facebook / Twitter, etc. It can get you countless links and it's a simple HTML code.
To promote your blog and drive in traffic, add your link to your email signature, request backlinks on other websites, and promote new blog entries via social networking sites. Stay patient, enjoy yourself, and results will follow.