The quest to create new and unique content is a challenge for most people who have a website. We're all knowledgeable people, but sometimes knowing what to write about is confusing. My suggestion: read the news.
Every day, there is likely something in the news that you can share your perspective on. Why you agree or disagree. Share your knowledge and expertise. Let people know where you stand.
People do business with people who they trust. That trust is developed online one post at a time. Those pieces of information tell the story about who you are and what you stand for.
Working in the marketing field, there are always plenty of things to comment on. Sometimes I come across items through the mainstream media that are worth discussing. Other times an interesting article will be making the rounds on social media. If I'm really strapped, I look at what other marketers are talking about and share my own perspective on the topic.
I think of posting as something akin to flossing. It's beneficial to do, but because the benefits come over the long-term, most people don't do it. Regularly posting meaningful, self-generated content is a good practice. It shows people who you are, demonstrates your expertise and builds credibility. It can also benefit your search engine positioning, especially in long-tail search terms.
As with flossing, the payoff for posting is likely in the future. It's the kind of thing you would benefit from starting now if you want to realize the benefits down the road. An added bonus: if you post AND floss, you'll have a great smile to show your new clients.