I never cease to be amazed by the richness, breadth, and depth of contextual information that customers will provide. You can garner this deep, rich context through observation/ethnography, interviews, and customer design sessions. We use all three techniques.
Whichever tools you choose, your goal is to understand:
* What are the important differences among types of customers?
* What are they actually trying to do?
* What is the situation that this type/group of customers finds themselves in when they are trying to do X?
* What's going on in their environment?
* What’s on their minds?
* What do they care about?