The first thing you need to do is get out of your developer-point-of-view. We tend to think in terms of forms, controls, buttons, lists, grids etc. And this tends to push us to solutions that are not always optimal for the user.
Users don't want to use our software. (except when you're programming games) They just want to get stuff done. So when desinging UI and user interactions it makes sense to start from there. Write down what a user wants to do with your software. Think about how a user would go about doing these things and what your application could do to make things easier.
Try to work with different tools than you use for programming. These make you think in UI widgets again. Start with a pencil and a piece of paper to sketch things, also try to think about the behaviour as well as the layout etc. If you've got a clear picture of what you want to build you can start thinking about how you're going to build it. That's when the widgets, buttons and pages come in.
