Jessica Harllee’s Sharing Our Work: Testing and Feedback in Design is a great article on different ways to get user feedback on designs:

To help choose our path, we create low-fidelity mockups and do concept testing with Etsy users who fit the target audience for the project. Rather than invest a lot of engineering time up front on building something we might not use, we often test clickable prototypes, which, while clunky, are cheap to create and involve zero engineering time. They’re mockups of an unbuilt interface, which also means we’re able to throw in blue sky features. Focusing on the best-case scenario of the feature lets us test whether sellers grasp the concept—realism and constraints can come later.