Determine what you want to store in there and be ruthless. If you don't use it regularly, consider it storing it elsewhere. Then, maximize the space by using organizational tools like risers for canned goods so you can use the full depth of the shelves. A lazy susan work great as well for deep shelves. Consider adding more shelves, using the door (like this organizer) and floor to maximize every square inch. If you are tight on space, consider ditching the boxes. They take up way more room. Place all like crackers or cereals in bags in a basket or container to save space.