Engage readers with well-researched and creative blog posts. At the end of it ask questions or feedback from them.
Post Ideas: At times you will just run out of ideas for post not sure what to do. use google and apps like Evernote to note down all that ticks in your mind. Something will surely turn into a new post.
Series of articles - Create a series of articles on your blog if the subject you choose to talk about is an extensive one.