When buying a microwave, consider the size of your kitchen and the number of people in your household to determine the appropriate size of the microwave. Over-the-range and countertop microwaves are two common types to choose from, with over-the-range models offering more space for larger dishes. When selecting a microwave, consider its wattage as it affects cooking power and defrosting capabilities. Additionally, look for features such as sensor cooking and multi-stage cooking to organize your cooking space and prepare food more efficiently.