E-commerce bloggers must carefully write keeping their audience in mind. Everything you post on your blog will speak for your product or service. Your interaction with bloggers in comments and otherwise will give you a direction.
Don't just type, talk to your audience. Blogging is way big a market on internet and people will like you if you do more than just providing information. Suggest, express, appreciate, criticize and have an opinion to build a relativity to a like minded audience. Make them feel that their visit to your blog matters to you.
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.