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.
Spare time to read - Blogging is not just about writing but also about research and reading. Read as much as you can to learn new things and ideas that you can experiment with on your own blog.
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.