Every innovation has been built on the work and experience of others. Even if you think you pulled inspiration out of your hat, you didn’t. Your ideas are the product of your experience, both direct and vicarious. The way to have inspiration is to cultivate experience: study what goes on around you the way a scientist studies nature.
In the case of user interface design, take a user-centered perspective. Study what users do. What do they do right and wrong? Where are their points of pain? Why? There’s an opportunity to learn every time a user curses a piece of technology. Sometimes the problems are more subtle than an emotional outburst, so you can also be inspired through systematic research, like a scientist. Do task analyses, counting the number of steps, the information to be memorized, and the calculations or conversions that must be performed. What have you discovered? What can be eliminated? Where are errors? How is language used? Inspirational ideas rarely come directly from the user, but a comment one gives or a statistic on the page can trigger inspiration in yourself. European designers evidently have techniques for deriving inspiration from the study of users.
Equally important to studying users is to study user interfaces. Look at the latest ideas for inspiration but also look at what users currently use –not just for what is wrong, but for what is right. Look at user interfaces of old technology for ideas, maybe even really old tech, not necessarily to make a metaphorical software equivalent, but for what was specifically good about it that you can re-create in digital form. Look at the UIs for unrelated products for what might transfer to your product.
The image of the brilliant designer summoning inspiration from pure intuition is an exaggeration. Certainly, some conscious or unconscious internal processing necessary, but if you’re looking for inspiration, first look outward, read, watch, ask, listen. Newton couldn’t think of squat until he saw the apple fall to the ground.