I took a good while to settle into a reasonable routine (I am posted overseas for a couple of years, and went solo as DH job couldn’t travel).
I learned how to do traybake meals - throwing halved baby potatoes on 1 tray and a piece of salmon or lamb chop or chicken joint (e.g. 2 thighs or 1 part-boned breast) on another a long with some veg, or adding the veg when the protein was half done. Some can be done in a single tray with potatoes or sweet potatoes and all. I experiment with different marinades on the chicken (feta cheese and thyme leaves under the skin, garlic/lemon/herbs marinade, piri piri marinade etc).
I have learned to use a measuring cup - 1/2 cup of rice is plenty for 1 (I sometimes buy the Uncle Ben’s boil in the bag for 1 bags for days I just want to turn things on and walk away). I make a batch of curry (what would previously have done the family 1 meal, not my previous batch size for the family) to eat that day and measure the rest in 1 cup portions into freezer bags, as that is a perfect size for me. I need 1.5 cups when I am doing the same at home for DH (when I go home for weekends).
I have a slow cooker and make 2-3 portions of a dinner in that and freeze 1, keep 1 for the following day.
I have learned to enjoy making a spag Bol with half a bottle of wine and a proper veg base (onion, carrot, celery) and doing a very slow cook on the hob. Or a couple of rich casseroles in winter the same. The leftovers, sometimes with some smash-type mashed potato with plenty of milk and butter, on an evening when it’s wet and miserable and I’m home late is much easier than pulling out the cheese and crackers.
I used to do stir fries a lot at home for the family - I rarely make those here. But I do a couple of different meals involving fresh pasta, bacon lardons and sauce make with eggs and sometimes wine (kind of Carbonara type), sometimes with mushrooms as well, or chicken instead of bacon, which are pretty quick.
I also like doing chicken and mushrooms (and onion/garlic) in a white wine/cream sauce, that can go with rice, pasta or mash, or over vol au vents, and freezes very well.
I freeze my sauces in Ikea ziploc bags (the smaller ones) laid flat, and then stack the on their sides. Because they are flat, they can defrost really quickly in the pot if need be.
And I’ve also learned to throw some extras into the oven when it’s on anyway for tomorrow - so Mediterranean veggies to go in a tomato sauce with meatballs tomorrow, butternut squash to make into soup, extra chicken breast to have in a cold salad, … And I’ve found I had time to experiment a little so now make my own pickled red onions occasionally to have in the fridge.
And I also use my freezer to put things away raw but marinading (Greek lemon chicken, buffalo wings, rosemary and garlic lamb chops, etc) and to do a bag of Mediterranean veggies that I can throw into a baking tray to cook from frozen (diced courgette, peppers, onions, garlic, tomatoes, mushrooms etc, tossed with oregano/thyme/rosemary, salt, pepper, olive oil and a dash of balsamic vinegar).
The other thing is to try and have ingredients that make cooking easy - I don’t have a microwave so can’t do ready meals. But I normally have a ready-made lasagna (they are good here) and things like salad, hummus, olives, tomatoes, mushrooms, lardons, cheese, eggs etc always on hand in fridge, and oven chips, frozen peas, some med veg and a couple of my freezer meals in freezer. And onions, garlic, lemons and some form of potato/sweet potato in the cupboards. So some days it’s an omelette with tomatoes and cheese, or other days I feel like dicing etc and will do a full Spanish omelette with loads of veg/cheese.
Enjoy experimenting as well - are there flavours/techniques that you didn’t do because others weren’t keen but that you enjoy or wanted to try? Now is a great opportunity.