Users visit websites and use apps to get things done, so emphasize the content of interest to communicate with your audience. Avoid design pollution that decorates the UI with non-communicative elements.

The foundation of user experience is the difference between the people on the design team and the people using the product. You can't ask users to design, but you also can't ask the designers whether their own design will be easy for the target audience to use.

Some UX designers (and many clients) aim to "jazz up" the design to supposedly engage users. This usually backfires because extraneous design elements get in the way of users' tasks.

The smaller the word count (and in general, the more concise your online communication), the more users will comprehend and retain your message.