The most useful advice I can give, which was also shared by several of my single friends when I surveyed them, was to cook what you're used to cooking, and freeze the rest. That is a good idea but isn't always practical. Plus, some days you just want something freshly made.
I've found that, being single, I can afford to buy better cuts of meat since I'm buying less than I would for a couple or a family. Always have something special on hand. In my case, that can be either a hanger steak or skirt steak, or a rib eye (although even when feeding only one person that can be way pricey.) I also like to keep lamb around, either chops or shank. When you live alone, there are going to be times when you're feeling a little lonely. When that happens, spoil yourself.
A trick I use, and it's one I recommend for everyone, not just for people cooking for one, is to set aside a time each week to do some of your prep for cooking. I chop an onion, usually on Sunday. I store it in a plastic container, and use only the amount I need for each thing I'm making. That usually means I chop a very large onion, and that leaves me in tears. This is sometimes therapeutic. If I have celery and/or bell pepper handy I'll chop those, too. Don't try to do this for longer than a week; the onion will lose flavor and other vegetables will soften if you do it too far ahead.
I'm not too proud to buy stew meat already cubed but if you don't want to do that, you can cube chuck or round steak for stews when you are chopping your onions and other aromatics.
By the way, you shouldn't count on chopping garlic ahead of time. It will lost flavor lots faster than onion will, provided the onion is in a well sealed container and refrigerated. I don't know if that's a scientifically provable fact or just my experience, but that's what I'm suggesting.
I'm going to share more thoughts, suggestions, and recipes on this topic as I'm inspired to and as I think of things. I would appreciate being linked to anyone else's suggestions and/or recipes for one.