…also always send progress pictures to Groupmes, group texts, Slack channels for #design, and so on. People don’t need to have an “eye” for art to give good feedback, and if you’re working with a defined “user group”, it’s a good idea to actively search for people who fit the description.
When you ask people for feedback, you get very different responses when you show a wireframe vs. when you show a polished UI design. Wireframe encourages people to comment on how things actually work, how the screens connect and what the structure of the page looks like. Whereas the UI design makes people think about the colours, the overall feeling of the page, how the content fits in, how the spacing is done etc.