Use FIFO: First In, First Out. In other words, use older product first before you open a newer package of the same product. Label and date your refrigerator's contents with the storage date. Leftovers should be eaten within 3 days. After that, put them in the freezer for long-term storage.

Cover your foods tightly to keep them fresh: Arrange contents of the freezer and refrigerator in an orderly way. It will help you keep track of what you have and keep temperatures even. Have sufficient air flow around products. This will make sure they maintain the right temperature.
Separate large amounts of leftovers into smaller containers. This will help your food to cool down more quickly and help you to keep your space organized.

Clean up spills with hot soapy water: Use shallow pans for large amounts of soups or stews. Large containers take longer to cool down. If not eaten immediately, cooked foods should be kept either hot (between 140°F and 160°F) or refrigerated at 40°F or less.