Write guest blogs for others and have guest bloggers on your blog to increase your audience.
Interact with your readers! Reply to their comments, emails and queries. Acknowledging your reader will make them come back to your blog again and again.
Content is the king - In the blogging world so diverse and big, you need to establish yourself with a distinction. the only road to it is good, original and valuable content. Be creative, different and surprise your readers once in a while.