Questions I ask myself to challenge my work
What is your 1. most important use case? What is you 2. most common use case?
What stands in the way of the most important use cases?
What is the most important thing in this design? Why?
How would you like your design to be perceived?
Are there things that could be solved visually, rather than through interaction & vice versa?
What is the design supposed to accomplish?
How well does the design scale?
Have you taken the context where the design will be used into consideration?