Write something useful for your readers. Share a relevant piece of information, an event update or a hack that makes a task simpler
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.
Tutorials: For Business Blogs, have tutorials that teach your customers how to use the product/service, what are the features of the product/service and keep your customer views open for them to read.