Are they very formal? Friendly? Upbeat? Precise?
For example, if they're wearing a suit and tie in an extremely hot summer, and they're very well groomed and are they asking direct questions about your background with narrow eyes and folded arms, this gives me a tremendous amount of information about the kind of person they are, where their concerns may lie, and how to provide the kind of answers in a format they'll prefer and appreciate.
By training yourself to be aware of the person on the other side of the table, it's remarkable the detail and level of personalised information you can pick up. Of course, this is a skill and takes time to develop.