Ask HN: How did you establish and maintain relationships with your first users?

I'm currently working on a side project and will be searching for early users / alpha testers in the near future. Our target demographic is established, but we want to keep an open mind as we iterate on the product. Anyone have any "dos" or "don't"s that you can share? Also, sharing a brief description of the product/service itself would be really helpful as well.

For context, I am working in the computer vision space.