The ever-wise Julie Zhou gives one of the most straightforward, non-jargon-filled explanations I’ve ever seen on how to tell if work is good:

Good design feels obvious — this is what it means to me today:

  1. “Good” design means it is a) valuable: you’re solving a real problem for people b) easy to use: people find it understandable, accessible and fast c) well-crafted: the entire experience feels designed with thought and care.

  2. If you cannot get a group of people for whom your product is designed for to generally agree that your design is good, it’s not good.

  3. If you cannot get a group of designers to generally agree that your design is easy-to-use and well-crafted, then it isn’t.

  4. The greatest frustration is feeling like you’re getting too much criticism from too many people (which, according to #2, means your design is not yet good). This is either because a) you’re working under too many constraints b) you’re not exploring solutions broadly enough, or c) the problem is beyond your current skill level.

  5. If you’re working under too many constraints that make it impossible to get to a solution that is obviously good, you need to voice that loud and clear with your team.

  6. If you’re feeling the frustration of #3 but aren’t sure why or how to make progress, the most powerful and effective thing you can do is take a swig of humility juice, admit that you’re stuck, and ask for help.

  7. Obviousness comes from conforming to people’s existing mental models. Don’t waste time reinventing common UI patterns or paradigms unless they are at least 2x better, or you have some critical brand reason to do so.

  8. Better design does not mean more design. Often, the most obvious designs are invisible.

Most lists of design principles and related things are truisms or platitudes. They aren't pragmatic enough to help designers make decisions. But this list offers a clear picture of what it feels like when your work isn't there yet and, by contrast, what it feels like when it's good.