Have a clear understanding of what it is that you would like students to learn. Clarify your objectives. Know what you would like your students to experience.
Experience is one of the major reasons for simulating an activity.
Clearly explain to students the purposes of the simulation,what their tasks are, and what your expectations are. If training is needed for students to successfully perform their tasks during a simulation, make sure that you provide that training. Within the bounds of reason, be a stickler for detail and accuracy. Strive for realism. Some of the space shuttle simulations we have seen at, other schools have had students going to other planets.