Originality - Focus more on the originality of content and on a consistent basis. It is a habit you will need to cultivate.
E-commerce bloggers can gradually choose to write curated content from other websites/blogs. That always helps because a buyer will generally not spend much time surfing. He/she will appreciate it if you provide most of what they are looking for.
Put advertisement but make sure that your blog visitor doesn't get irritated when ads pop up one after another like a flood.