Ask your customer to pretend that you are the product. For example, if your product is a blood pressure monitor, you would be doing the things the monitor does: taking blood pressure, displaying information, etc. Have them walk through the day and map when they are interacting with you (bonus points if you really spend the day with them as their product!).
Pay attention to the following:
- Where do you sit?
- When does your customer engage with you?
- Do others interact with you too?
- What do they need from you?
- What do you do in your down-time?
- What aren't you doing that you could be?
By being the product, you can recognize where your product meets or exceeds their needs, and where it falls short.
It might feel silly, but it might also lead you to a deep insight that can be game-changing.