If you must continue to use a microwave oven. . .
Have it checked regularly for leakage, especially the door, which is prone to leakage
Never open the door while the oven is on
Stand at least three feet away (especially children) from the oven when in use to avoid the cumulative effects of even low level exposure. The lens of the eye is most at risk from prolonged microwave exposure because it has no way of dissipating the energy thermally or otherwise
Avoid microwave cooking of frozen foods and commercially prepared meals, especially if they are to be cooked in their packaging
Use non PVC cooking containers whenever possible
Discourage growing children from eating microwaved food or using a microwave
Be aware that the majority of restaurant food is now microwaved using large commercial ovens. These pose even greater potential risks to users, and those using them should be warned.