There is only 2 of us, but yes I do meal plan, sort of. I don't think I do anything special, and as I said Christmas leftovers were incredibly helpful in January. I think the main thing is that I mostly shop at Aldi, and I cook 90% from scratch. Its not anything very complex or difficult though. The only thing I cannot do is bread, its consistently bloody horrible.
My main meals per week more or less consists of 1 meat, 2 chicken, 2 fish and 2 veggie main meals. I do a stock take of what I've got in the freezer and pantry. I do a rough meal plan using what I've already got and the meals formula as a framework. Then I make a shopping list which will feed us for a week, but if there are any special offers that we will eat, I ditch the list and buy those instead. I sometimes buy a huge thing of mince or chicken and batch cook so there is usually something in the freezer for can't be arsed days.
I usually do at least 3 really simple cheap main meals per week, like baked potatoes with beans and cheese, broccoli or mushrooms in cheese sauce with pasta, egg and chips with tomatoes and peas, homemade pizza and salad. These are not on the meal plans, so the weeks food usually lasts at least 10 days. I can do this because I keep the larder topped up with basics.
Breakfasts are usually eggs, avocados or mushrooms on toast, eggy bread or h/m pancakes, tattie scones and bacon. DH also has porridge with jam. Lunches are usually leftovers, sandwiches or h/m soup with bread or ryvitas.
I make plain cakey type things as hole fillers, like scones, raisin muffins, and flapjacks. We also have a few puddings, not everyday, maybe a crumble or microwaved 'steamed' pudding. They may not be good for you, but are very cheering when dinner is a bit basic or sparse.
As I say, its not rocket science, but the thing I do have is time. I cannot work due to ill health, but that means I do have time to cook from scratch even if its a baked spud.