Whether you're an experienced hunter, or just starting to consider the idea of hunting to supplement your food stores, there are some things you should think about. Some are general hunting concepts, and some are more geared to survival hunting in hard times.
You'll need a location as close to home as possible. If it takes you even a few trips to find and harvest an animal, and your hunting spot is more than a few miles from home, you will quickly erode any financial benefit of hunting over just buying meat. Of course, you'll need a spot where you are allowed to hunt. In the West, this will likely be public lands, while in the East you'll probably need permission from a land owner.
There are several hunting methods; Ambush, spot and stalk, flushing, baiting, and calling are just a few. Of all the hunting strategies, variations of the ambush are by far the most successful over the widest range of hunting situations. The reason is simple. Your prey has incredible hearing, and vision that recognizes movement far better than ours. In ambush hunting, you let the animal walk into an environment where you are silent and still (there's nothing to see or hear). In other forms of hunting, you are walking, making a visual and audible spectacle of yourself. For survival hunting, ambush hunting requires the least physical exertion making your calorie output per pound of meat harvested even lower. Regardless of the method you choose, hunt for the half hour before sunrise till half an hour after sunrise, and the half hour before sunset till the half hour after sunset. These are the most active daylight hours for most big game.
To ambush hunt, find a place to sit where you can watch a clearing, an open hillside, or a well used game trail. Sit close enough to the open area that you can shoot any game animal that crosses your view. If it's legal in your state, you can add bait like a mineral lick or corn to the area you are watching. Sit still and move nothing but your head, slowly scanning for animals (remember, animals see movement). Hunt alone so you aren't tempted to talk or whisper to your buddy. Animals have incredible hearing, and we aren't as quiet as we think we are.
It's really that simple, hold still and the animals will walk out in front of you. You will be rested and have a good (preferably prone) shooting position to make an accurate shot at a standing animal. Contrast this to the hunter who scares up an elk while hiking. He has to shoot a running animal offhand with a pounding heart while breathing hard. No wonder ambush hunting works better!
Hunting can be a an integral part of sustainable living or a valuable supplement to your stored food in hard times, but be careful about relying on it as a major food source. In hard times, you won't be the only one hunting for food, and the game populations will dwindle. Just be aware of the population density, both of people and animals, in your area and plan accordingly.