Some people (like me) only have one business blog. Others have many. But the first step towards having a useful and productive blog is to ask yourself the question, 'What am I blogging... ABOUT?'
Too many blogs wander from one subject to another, or are cluttered with a visually irritating amount of advertising banners or icons, to really achieve any purpose. If your blog isn't about one specific thing (or if it lacks a theme) then it can't really be called a business blog. What I mean to say is that you must always be mindful of your blog's ultimate purpose while adding content to it. Ask yourself, 'Why would anyone read what I'm writing?' You need a good answer to that question before you start adding any kind of blog content! Remember the basic goals of any business blog: 1) To build brand awareness. 2) SEO. 3) To act as a newsletter and improve customer relations. 4) To establish credibility.
But at the end of the day, a business blog has only one function:
SALES
Nothing happens until something is sold. If somebody comes to your blog, then they probably came there for a reason. If (for whatever reason) someone is exposed to your business blog and comes away having their want or need met, then there is chance that you've made a sale - or at least established the kind of author/readership link that might lead to a future transaction. Bottom line: You're blogging for your visitors and not yourself.
Lastly, always, Always, ALWAYS drive traffic to your blog. Do it in every conceivable way. A couple of free programs are TweetTrafficRush and ExitFire. Those are free to use and they are merely two ideas for bringing viral traffic to your blog. Blogging is a vast universe and becoming an expert at it is something that will serve you well when it comes to online business. Just remember to never stop learning and never stop growing. Most important of all, never, never, never quit!