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.
Forums are good way to drive traffic if you are regularly posting something.
KISS - Keep it simple stupid. Always keep your blog simple, organizes upto the point. Do not over-flood with unnecessary posts or irrelevant images and keep your content straight-forward.