Jaaxy research is a great way to go. I find also that ideas are constantly coming to me and I write them down right away.

Do some keyword searches that relate to your niche. Sometimes I use the Google Keyword Planner or Ubersuggest. It shows what people are searching for related to your niche and then I get all sorts of ah-hah moments to content writing ;)

What's your niche? What are your interests? What's your expertise? Write about what you care about.