Hugely open question, which is not really answerable, there are thousands, maybe a million ways to monetize a blog. The most common are AdSense (not so popular with BH-ranked blogs), Amazon Affiliates, and other CPC companies. Locker pages are a very common BH tactic to monetize extra pages.
Email submits, lockers, CPC, banners, shit if you're clever enough to twist the idea of a blog a little bit, you could get it to number one for a local search term (idk, "dentists in nyc") and then offer an advertising banner to local companies for $400/month, if there was enough traffic. Think outside the box, the main thing is to get to number one, that's where the money's at.