The once a month cooking (OAMC) method makes extensive use of the freezer by cooking enough for several meals at one time, then freezing portions, either family meal size, or individual size. For another form of planned leftovers, simply cook more than you'll need and plan to freeze what is left over for another day.
Raw or cooked. Some cooked meats (especially ground beef) take on a different flavor. Some people object to this; some don't. Raw meat especially needs to be packaged well. Use freezer bags, mylar type of potato chip bags, or other containers that you can remove the air from. Press the air from bags and be sure they are sealed well before freezing. For the chip bags, fold the top down several times and tape all the way around the bag. Masking tape works as well as more expensive freezer tape if you run the tape over itself this way.
If you use a different type of container, use one that is barely big enough to contain the meat, to leave as little room for air as possible. If you're freezing meat that can stand it, filling the container with water to with a couple of inches of the top will help. Otherwise, use gravy or sauces to cover the meat.
Get a good chart (below) for handling fresh vegetables before freezing to keep the best quality. Most, (but not all) fresh vegetables must be treated first by precooking quickly in boiling water (blanching). Most canned vegetables freeze with no other handling, but they sometimes turn out soft or limp when thawed - fine for stews, soups or casseroles but you may not care for them as a separate side dish.
Handle these the same way that you do vegetables, but many more fruits than vegetables can be frozen as is. Peaches, apricots and bananas are fine just dumped into a plastic bag or in a bowl and put in the freezer. You can eat them frozen for a treat, or use them in cooking or make a slushy drink from them with your blender.
Freeze milk, cheese and eggs for future use when you get a good deal on them. Milk might need to be stirred to return to it's former consistency; cheese may crumble and eggs may become grainy, so plan to use frozen dairy mainly for cooking. Unless, of course, you don't mind the changed texture. Freeze eggs by mixing the yolk and white thoroughly. Yolk doesn't freeze well by itself, but the whites do. If you put one mixed egg in each compartment of an ice tray, you can take out exactly how many eggs you need for baking, etc.
'Bread' includes rolls, cookies, cakes, etc. Double wrap bread before storing it in the freezer. Bread sacks are permeable plastic - that is, they 'breathe', so put the bread, in it's sack, into another freezer proof bag. Store loaves of bread vertically rather than horizontally, especially if you've experienced hard and soft or damp areas on a loaf after it was frozen for awhile. This is due to uneven temperatures. If you store bread loaves upright, and still have the problem, only slices from the top and/or bottom will be affected, instead of the whole loaf. Surround cakes and so on with other foods as much as possible. By that I mean, don't put it on the bottom or top of the freezer to avoid uneven temperatures. If it's in the midst of other frozen foods, it will keep fresher longer.