While any designer should reference Ben Schneiderman’s Eight Golden Rules of Interface Design and Dieter Rams' Ten Principles for Good Design, I’ve added these four principles to help guide me in my work.
Make capabilities clear
If users can’t tell what something does before they interact with it, then change it until they can.
Fewer decisions lead to more action
Allow users to concentrate on what matters by breaking up decisions into phases. This will make it easier for users to confidently commit to a task.
It only works if it works together
Every website, application, or tool has one user experience. If something feels out of place then modify it until it's consistent with the overall look and feel.
Looks matter in design, but not at the expense of falling short of users' expectations. Don't promise what you can't deliver or you'll lose trust.