It is very easy to setup a blog for a local business. Many webhosts have a push button install of all the popular blogging platforms or you can use an online hosted version. Maintaining a blog with a host takes a little more work, but gives you more control. A hosted version can shut down a blog for any reason and then the local client will be without a very valuable asset. Once the blog is setup then a theme can be installed to give it a nice look. There are many themes available to download for free or you can hire a designer to create a custom look for your client. Sometimes the blog can be the only web presence for the local professional or it can be a supplement to their main website.
It is important to train the local business owner on how to post content to the blog. Create an account separate from the admin account, so they don't accidently change any of the settings you have configured. Show them how to save a draft and then publish it for all to see. Once they understand how it works you can let them go on their own.
The local business professional should make regular posts to get the best result from the blog. The search engines love fresh content and it will help with their SEO rankings. The posts should be informative and give a reason for the reader to stick around. The idea is to show the professionals knowledge and establish credibility as a local expert. Many times a prospect will search the web first to find information about their situation. If they find a lot of information from a local source then they are more likely to hire them.
This is a great service for you to offer and can be highly effective in the right situation. Just remember that not every local business needs a blog and only suggest it for the ones that can provide regular and informative posts.