Start with the simplest thing that could possibly work.
This is an agile concept (actually from Extreme Programming, technically), but it’s great for helping you get unstuck from any creative problem (see other tips here and here). You have to simply resolve to not worry about whether your design is going to be any good, and just go ahead and do the design. Or the writing. Or the coding. Whatever it might be. The goal is to get the first draft done. First drafts are usually awful, but you can’t get to a good second (or third, fourth, fifth, hundredth) draft until you’ve written the first draft.
For example, if I have to design a new user interface component (and I’m not a designer at all!) I will just take a pen and paper, or use Balsamiq, to create a rectangle that’s going to be the outside, and inside it I’ll put the buttons and fields that seem to me at that moment to need to be there. My only goal is to get something that could possibly, in some limited fashion, capture or present the information that was necessary.
This is the only effective way I’ve found to get going on design problems. Since I’m not a designer, I always have a “block” against designing. As a user of many many different interfaces I have some intuitive sense of what’s good and bad. But I try not to use that sense at all when doing this exercise, because my goal is only to get something that could possibly work down on paper (or into Balsamiq).
Once I have that first crappy design, then I can start mucking with it, improving it, reviewing it with others, and so on. In fact, by getting started in this way, if all the other conditions are right (i.e., it’s not too noisy and I don’t have other distractions) I sometimes go into a flow state and get very involved in creating an actually good design. But I have to start with the first draft, which I know is going to be terrible, and is just something that could possibly work.
What do you use to get unstuck?