Blogs can be powerful tools to establish your expertise, position you as an authority in your field, and showcase what it would be like to work with you to clients.

Sadly, few live up to this. Most are dull, full of mediocre content and rarely updated.

As a result, they end up abandoned – discarded like a broken child's doll tossed from a car window on a motorway as the family heads off to other things.

So, of course, it doesn't win any business for you at all.

The first thing you need to to do to avoid this is to pick the right topic for your blog.

Blogs that win business for consultants, coaches and other professionals are, of course, almost always focused on a business topic that the professional covers as part of their services.

But what specific topic to choose?

Rather like the way you choose a niche to focus in for your business as a whole, your blog's primary topic needs to meet three criteria:

• You need to have genuine expertise in the area. The web is far too full of mediocre, generic information – it doesn't need another blog giving out more of the same.
• You need to have a passion for that area. To have an effective blog you need to update it at least weekly – that means lots of content. You need passion to keep cranking that out week in, week out.
• There needs to be a market for the topic. It needs to be in an area where establishing your expertise will bring you clients. And the more valuable your blog is to potential clients, the higher value you'll get.

My advice is to go narrow. Pick a broad topic like marketing or finance and you'll end up producing bland, generic posts that try to cover everything. And there'll be too much competition for anyone to ever find your blog.

Instead, pick the one aspect of that topic that you find fascinating. For me it was marketing and sales for professionals – and consultants and coaches in particular. When I first started out, there were just a handful of blogs in the area so this allowed me to establish myself quite quickly.

A lot of folks have jumped on the bandwagon since – but I've managed to maintain and grow my popularity.

If you're into marketing, maybe it's copywriting or ad design, or long term nurturing you find the most interesting. Write on that and you'll produce in-depth, insightful material that will attract visitors and potential clients.

I'll write more on how to get visitors and potential clients to your site shortly. But the first step is to have quality, in-depth content so that when they do arrive they stick around. And it builds your credibility so they're ready to buy from you.

You need to hit the right tone too. An academic paper or treatise on the latest trends in your specialty may mark you as an expert to your peers – but it's not going to impress potential clients much. What they're looking for are tips, ideas and practical suggestions on how they can improve their business or lives in the areas you focus in.

And you don't need to be the world's leading expert either. You can be the guy that makes complex concepts simple and practical. Or the guy who's blog is insightful and also entertaining. Or the guy who's the expert is a particular geographic area.

The next article in the series looks at creating valuable content for your blog.