I started using Text-link-ads on some of my sites with PR3 or more .. I got some nice money from this and it seems to pay better than adsense in my case. I also started selling ad space in my sites ... that can also be a good idea to monetize the projects
Niche marketing is the best. Find a niche, and market within that niche. You will quickly see people within that niche talking about your service, and start getting word of mouth referrals.