Blog for the fun of it and show character. It is immaterial how many write about a particular subject, it is how you write the matters.
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.
Make your posts visually appealing. It really helps in grasping the attention of the reader and adds value to the post.