A blog might be good but honestly a lot of clients don’t know what they want so a tech blog is unlikely to bring them your way (if they’re reading a tech blog chances are they’re already developers and might not need your services). I personally write but I do it more for the fun and for giving free advice rather than a way of gaining clients.
It is not my business yet (I’m still just a contract software engineer) but I’m going to look into this next year. I know one of my ex bosses has a successful small business developing bespoke business software so I think it’s a good market, and if anything will make a few lucky people happy with great software instead of the usual Oracle/SAP/Salesforce garbage.
My email is in my profile. Feel free to get in touch if you want some advice.