How do you evaluate UI designers?
The two main techniques for evaluating a user interface are 1) Empirical Evaluation (testing with users) and 2) Heuristic Evaluation (based on a set of rules). While empirical evaluation is by far the best technique, mastering Heuristic Evaluation is also a necessary skill.
How do you ace UX design test?
Go through the UCD- HCD Methodology thoroughly. Read the job description thoroughly and be prepared of what competencies they are testing you for. Practice the UCD process on a sample test to be able to complete the exercise in 4hrs, 8hrs, 10hrs respectively. Ask questions (to the recruiter, interviewer).