Now that you've figured out which topic you want to cover, you've got to start generating unique and useful content.
I ran into that situation early on in my blogging days, which started in 2004.
Over the years, I figured out ways for the content to come to me.
One thing I did was to take a page from the book of home building expert, Tim Carter, and his site, Ask the Builder.
Based on his extensive experience building homes, Tim made himself available to answer questions related to home repair and building.
He would then answer them on video and in text in posts on his blog.
I also use Google Alerts to help me with ideas to create content by tracking keywords to find relevant news stories, blog posts, etc.
Next up, I'll explain both setting up your site to accept questions, making videos, and how to use Google Alerts to track news stories.