It's good advice, but I don't stick to any particular niche. If you do relationship advice, then putting that you're a licensed family threapist will help. It's not so easy to narrow it down if you write in a dozen different topic areas.

I've changed my bio a few times, but I don't think it's made a difference. I add followers when they like my stories and when they agree with my comments. I also add a lot when something I write goes viral.