Series of articles - Create a series of articles on your blog if the subject you choose to talk about is an extensive one.
Newsletter: Newsletter is a great way to keep your audience glued on to all that is happening on your blog. It is best way to know who your loyal audience is.
Use technology - Social plugins and SEO tools are a great thing to market your blog or a blog post. If you do not know about it, then learn it. It helps you reach out your audience in a better way and also improves the ranking of your blog.