First remove all items from inside the refrigerator and wipe down shelves, storage areas inside the door and especially the vegetable crispers (this tends to be the area of most spoiled food-causing the smell) with a wet rag, follow up with a dry rag to ensure there’s not too much moisture on shelves.  After cleaning, and once you’ve placed everything back into refrigerator place an open box of baking soda to keep your refrigerator fresh smelling.