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.
Guest post, guest post, guest post. I write guest articles for other blogs and also invite bloggers to contribute towards my blog. In this way network is built. Both the blogs get famous.
Grammar - Depending on the language you use, blogging just makes it imperative that you are reasonably good with your grammar skills and proficiency if not a master. Remember your audience is a mix of both; the ones who are experts and the ones who are not.