Depends on what you know. What do you know, that you think people would be interested in, but is not that well covered on HP?
Brainstorm session: write down everything you know something about, be it "shopping for children's cloths cheap at thrift stores" to "7 ways to feel better in the morning" to "My review of (item X)" Come up with at least... 20-50 items. Then search HP and see if it's been covered. If not, WRITE IT!