Something I like to do is browse questions here, or different forums related to whatever site I'm working on, and see if something people are talking about is something I could write on. I've gotten a few blog post idea's from doing that, but it doesn't always work. I also set little "rewards" for me to work towards. Like, i won't go smoke, or watch a tv show, or play a game or whatever until I've written so much. Bribing myself works wonders.