I have a blog that targets educators.
One of the fastest ways to build your reader ship is to build a simple landing page with the key "WHY YOU SHOULD READ MY BLOG" front and present. (a video works great, even if its slides with a voice over) Using capturing tools like, email, "like my (add social profile)" then I would create a Facebook campaign targeted your audience, I would do the same on LinkedIn.
That is a simple real world example that I use for clients that are on a low budget. Let me know if you have anymore questions.
