1/ Have a clearly defined written 'purpose' to help ensure that your blog content will stay on target and on topic so that you deliver what your readers expect every time. Consider your business blog like a magazine. People subscribe to magazines only when they have a sense that the content in the magazine will be consistently relative to their interests.
2/ Blogs are not the place for a heavy hitting sales pitch but don’t go to the other extreme either. One way of introducing your products without being pushy is by choosing a layout that allows you to feature some of your products on every page.
3/ Finding Your Voice: Avoid writing your business blog in 'corporatese' and use a more conversational tone. The most effective and popular business blogs have a personal voice so try out a few key company representatives as the blog personalities.

One very last point: Blog marketing is very much 'relationship marketing.' Responding to reader comments and questions is an important duty of a business blog writer or another assigned person within the organization.