Ask yourself if what you make solves a problem for you.
Ask yourself if you would use the solution to the problem that you're solving.
Ask yourself if what you make solves a real problem, or an invented problem.
Ask others if what you make solves a problem for them.
Observe people when they use what you make.
Listen to people who comment on what you make.
Observe and listen to people who are angry and frustrated with your solution to their problem.
Test different ways to solve the problem. Pick the option that cause the least frustration, and make the most sense.
