Grammar - Depending on the language you use, blogging just makes it imperative that you are reasonably good with your grammar skills and proficiency if not a master. Remember your audience is a mix of both; the ones who are experts and the ones who are not.
Newsletter: Newsletter is a great way to keep your audience glued on to all that is happening on your blog. It is best way to know who your loyal audience is.
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.