Bulky packaging takes up far more space in your freezer than you may realise. Without their box, you can slide pizzas against the walls of a chest freezer, taking up a fraction of the space that they would with their full packaging. Label your food as you place it in the freezer with a marker so that you don't find yourself in trouble down the line when all the frozen food looks the same. I like to use masking tape for my labels.
This is especially handy for those of us who use a chest freezer. By dedicating areas to particular foodstuffs, you know that you are going to be freezer diving in the right part of the freezer from the very beginning. Stack bread beside milk, because these are your everyday staples, group frozen dinner portions together by dish and in portion sizes to suit your family.
If you have drawers, designate different drawers for different foodstuffs.
Liquids like soups, stocks and even leftover wine can be frozen flat in ziplock bags and will take up a tiny amount of space. Label them with the date, and what is inside and stack them in one area or drawer of your freezer. This is especially helpful if your freezer space is limited.
Treat your freezer like it's a shop. Keep a sheet of paper and a marker beside your freezer with a list of what is in there at all times, and you'll never find yourself hoarding things you don't need. If you have five different kinds of soup in your freezer, do not consider making more soup until you have eaten your stash.
Don't throw 25 chicken breasts into the freezer. Portion them either individually or in family-sized portions and store them side by side. That way, it is easier to defrost and there is less likelihood of the chicken languishing in the freezer for the foreseeable future. Choose the right containers. Don't use containers that are too big, because they will hog the space, or flimsy bags, because they will disintegrate in the freezer. Treat everything that goes into your freezer with care, and it will continue to be the kitchen workhorse you need.