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.
Given that your blog has great content, it should also be presented in an organized way. Link within, smart layer are some must have widgets for the same.
Put advertisement but make sure that your blog visitor doesn't get irritated when ads pop up one after another like a flood.