I'm not an expert by any stretch, but this is how I started. First google freezer meals, or once a month cooking. That will link you to tons of websites that really know what they are talking about. They will tell you what sorts of foods freeze well or not, how to portion, recipes, etc.
I started by just doubling some of our favorite recipes. Like spaghetti, instead of making one batch of sauce, I made 2 and froze half. NOt the noodles, they are easy to make, but I browned double meat, then added the sauce. I let it cool in the pan, then put it in a freezer container. Voila, pull it out, dump it in, it cooks while the noodles cook and it's done. If you use plastic storage bags, just dump it in, lay it on a cookie sheet in the freezer and when it's frozen it will be nice and flat and not take up much room. THis works easy for all saucy kind of things like chili and soup.
Casseroles you can make in your own dishes if you have a ton or some people line the dishes with extra foil, then freeze, then take the frozen casserole out and wrap the extra foil around making it the container. When you are ready to defrost and cook, just pop it back into the original container, defrost in fridge then cook.
What kinds of food does your family eat, then we could give you suggestions for how to prepare it.