This is a well-written article that has a lot of good ideas. One thing I’ve found to help is a practice James Altucher promotes. Everyday he thinks of ten ideas. Even if they suck, he jots them down.
The thought process goes: if I do this everyday for 30 days, I have 3000 ideas. At least a few of them have to be good, most likely more.
I don’t do this everyday, but I do regularly do it when I’m stuck. Dozens of story ideas have come out of this process. Laziness keeps me from doing it everyday, otherwise I think I’d have endless material to write about.