Telling your own or someone else's story is one of the easiest, yet most effective ways to create content that spreads because you are no longer alone promoting it.
Besides, the blog always looks more trustworthy when there are known niche experts taking part in its life.
While I love reading expert interviews and I always see great results when publishing interviews on my own blogs, this type of content has been over-used recently.
Related: 3 Sources for Great Content When You're Short of Ideas
Ask controversial questions to stand out.
Steve Counsell told me an interesting story of how an open question can help to lead the discussion in a most interesting way.