Image speak - A lot of bloggers tend to ignore this, but the images on your blog speak a lot for what you write. Use good quality images and make sure they express your written stuff in utmost simplicity yet precision.
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.
Picture talk: Use of images attracts more eyeballs. It is humanitarian. Even if it is a data centric post or a theoretical one, have an image that speaks significantly for your post.