All the time - I'm a consultant UX designer and software engineer, after all.

The first step is always to try to become the user; get into their mindset and see their perspective. It's the only way to do any useful work, because what people actually want (note: not what they _say_ they want) is far more important than your rarified vision, particularly if you're not in the target demographic.

Client interviews, surveys, use-case construction and so forth are all useful tools, and they're well-documented and well-understood. However, I'd caution against relying on them completely. Once you have some experience, you'll find that your professional judgement is the most reliable modulating factor for software design.

As I've said elsewhere, I'm also a big fan of pencil-and-paper prototyping, regular revisions and very regular client feedback.