In this case you'd make the approach more internal to you, your service/product, your perspectives, and so on:
- You aim for what seems like a reasonable standard of quality in the first place
- You actively gather & respond well to customer feedback. Provide a personal touch if it helps you gather feedback & deliver quality.
- You develop a superior perspective on the dynamics of your own product: How & when it works well
- You start to place your customers into theoretical groups
- You test the dynamics (price reaction, product change reaction) of each group
- You rank the groups by most-interesting and refine the ranking over time, asking how this information informs your pricing & development plan moving forward
- You tighten this decision-making loop, making it fairly frequent (usually weekly at least) & ask how it's working out for you, and what needs to change
You can be doing this with < 10 customers if you want. Good luck to you