How do you market a small business offering custom prototypes and creative solutions?

I run a small business in Colorado Springs where I design and build custom prototypes, interactive exhibits, and other creative solutions for startups and innovators. While I’ve had some success with word-of-mouth referrals, I’m looking to grow and reach a wider audience. I’m curious, how have other startup founders or small business owners effectively marketed niche services like this? Have you found success with social media, partnerships, content marketing, or something else? Additionally, do you think focusing on a specific client type (e.g., startups in tech or education) makes a big difference? I’d love to hear any tips or lessons learned from your experiences!