There is a great post below by Daniel Geey of Sheridans on Instagram (link below). In it, Daniel suggests that people that want to work in sport should maintain a knowledge journal. A knowledge journal is a list of what you've consumed, when you consumed it, and what you've learned.
That is the perfect way to think about a professional services blog.
Next time you read a relevant news bulletin on the BBC or consume the latest industry research, write down a few words on what it was you learned from that piece, why it matters in the context of the industry and what your clients should do as a consequence of that knowledge.
You'll be solidifying that knowledge for yourself whilst delivering valuable and timely advice for your clients and prospects. Stop thinking about your blog as a blog and start seeing it a place to catalogue, explain and deliver value for clients.