Our only freezer space is the freezer on top of the refrigerator. Just to make life fun, the fridge is the however-old one of questionable maintenance that came with the apartment. Dependable, not too much of an energy hog, but still not exactly top of the line. Things do get freezer burn if we're not careful. There's also the option for avalanches if stacking isn't done well! I thought it would be useful to post an overview of what has worked for us when it comes to utilizing our freezer. I'm also including ideas on how to stretch leftovers, so that not-quite-enough becomes plenty for all.
I'm gradually using more glass than plastic when storing food. With glass, it's extra important to leave space a the at the top of each jar to allow for the expansion of the food as it freezes. I always leave at least one inch, preferably two inches, at the top. When I haven't allowed enough space, I've often thawed the food so I can throw out the jar because the bottom broke off! In those instances, I throw out the food too, just to be safe. I don't want to take chances with glass shards.
Quart jars hold 3 cups/24 ounces, which is two to three servings depending on the food. Pint jars hold 2 cups/16 ounces. I will re-use commercial glass jars for this, or I use my regular canning jars. Be careful with the commercial jars as I've found them to be a bit less sturdy than the canning jars. I cool off the food in the fridge, and then transfer it to the freezer.
Keep in mind that some foods will soften due to being frozen. I believe this includes pasta and beans. Detailed information on freezing foods can be found here.
Leftovers are frozen by serving amounts whenever possible. Don't forget to label and date the packages, and to keep them rotated. Not everyone needs to be able to identify frozen broths by color, even if I had to learn the hard way!
Some leftovers are intended as single-servings, often for me to take to work for lunch. For these, I will set the food up ready-to-eat: Leftover chicken with the stuffing and veggies in the same dish, either side-by-side or stacked; spaghetti with sauce on top and perhaps cheese; etc. Essentially thaw-and-serve. I can take the food out at bedtime, put in the fridge overnight, and then take it to work with me for lunch the next day. I do not refrigerate it at work as it is still slightly frozen and will finish thawing in the morning, while it also cools my drink. I've done this with rice dishes, spaghetti, meats, and veggies - just about anything. Often I pack the food with a pat of butter on top as the extra moisture while reheating seems to help. Then again, I like butter on just about anything, so your mileage may vary on that one.
When there are enough leftovers for a second meal, I will often freeze it in Quart canning jars. For the three of us, one quart jar with an added side (say, soup with garlic bread or a salad) is enough for one meal. For two of us, just the quart jar is enough. For a larger family, or unexpected company, you can adjust from there. Plan on two quart jars for dinner for four, and add sides to feed five or more.
Planning on three people, and your parents stop by? Salads and bread for everyone, and add pasta to the soup while it heats. You could also add a can of veggies to stretch it; I keep canned carrots and potatoes on hand for this reason. They need heating rather than cooking, so they'll cook at the same speed as the rest of the soup.
To freeze soups, I add 2 cups of solids and then pour in the broth until the jar is full (1" to 2" below the top). The jar is labeled with the contents and date, and frozen. Meats are often shredded or diced, then packed gently into jars and frozen. Veggies are frozen in the juices they cooked in, or in vegetable broth or water depending on what I have. I make sure the water covers the veggies so that they'll be in the best shape when they come back out.
Soup can be used for planned-overs by using it as the base for a potpie. Follow the directions for the potpie with these substitutions: drain the broth of your soup into a measuring cup, and add water if needed to get the amount of broth needed for the soup. Use where the recipe calls for broth. Add the solids from your soup when the recipe calls for the veggies, keeping in mind that it may not need quite as much cooking time since your veggies are already cooked. If there is meat in your soup, you will not need to add meat to the pie filling. Follow the other directions as given. This turns two or three servings of soup into six to eight filling servings of potpie!