Beauty is in the eye of the beholder. Each organization, school, and has a particular way that want forms to be performed; while one may think a certain way of moving is beneficial, another may think the same way of moving is detrimental. However, there are some things that are common to any type of forms performance.
Always perform a form in manner you want to perform it in competition, do not just “go through the motions” when practicing. You are trying to develop muscle memory for the movements; you do this by repeatedly performing a movement in the proper manner until you body can perform the movement without conscious input from you. Tiger Woods does not think about swinging a golf club. He thinks about range, wind, terrain, etc. and then swings. His rigorous practice swings have made his swinging movement automatic.
In a form, you are fighting one or more imaginary opponents. Practice the form as if you were fighting real opponents. Each movement should be made with power, speed, and precision. You would not use a short, half-ass block in a real fight so do not do it in a form. Behave as if you were fighting real opponents. In a real fight, you would not be expressionless and quiet. You would look fierce, glare, exhale loudly, and emit blood-curdling kiais.