As I write, I am about to celebrate a major birthday (yes, 40 … again), and while I’d rather not think too much about my face, my bum and various other body parts – I’d rather not think about them because, in fact, I don’t dislike them even half as much as the world tells me I should – this seems a good moment to take stock. For half a century now, I have been a hearty eater (ie a greedy pig). For 30 years, I have been a cook: first a rubbish one, then quite a competent one. For a quarter of a century, I have written about food, or edited writing about food by other people. What, then, have I learned so far? What are the bullet points? Uncap your pens, and we will begin…

1 Let’s get the pomposity out of the way. Food, and by extension the ability to cook it, is very important. This cannot be overstated. Good food makes people happy and healthy. It punctuates the days in the loveliest and, sometimes, the most memorable ways. It connects to kindness, to generosity and even, I think, to sanity. But you don’t have to take my word for this. “Good cooking is a moral agent,” wrote Joseph Conrad in his introduction to the cookbook his wife Jessie published in 1923. Joseph bloody Conrad. I rest my case.

2 Tomatoes should never be kept in the fridge.

3 People are getting fussier. This isn’t only true of the young. People my age (which, as I said, is 40) are getting fussier, too. Some of this, admittedly, may be the result of the best intentions (eg born-again veggies), but it doesn’t change the fact that there’s a certain amount of aggro involved in accommodating all the various intolerances, loathings and nervous states.

4 Spaghetti carbonara is the best stand-by late-night supper ever invented, and it comprises pasta, pancetta, eggs, cheese and black pepper. Add cream, and you have ruined perfection. (Don’t email me about this.)

5 I am suspicious of people who do not have a bag of peas in their freezer. What do you eat with your emergency fish fingers if not frozen peas? Frozen peas are so brilliant. Stew them with butter, any old lettuce leaves and a few sliced spring onions, et voila, you have petits pois a la Francaise to go with your roast chicken. Alternatively – this is nicked from Nigella – roast a garlic bulb and then blitz it with some parmesan, olive oil and frozen peas. Spread on toast for delicious and posh-seeming crostini.

6 People with the swankiest kitchens are very often the worst cooks. Knowing this helps with kitchen envy, from which I suffer badly.

7 Whatever people say, there is no substitute for butter. I like toast on mine. Also, salt: chefs use a lot more than the rest of us, which is why their food tastes so good. When in doubt, add salt.

8 If someone is feeling a bit fragile or sad, give them a dinner that involves roast potatoes: starch for the soul. (While we’re on roast potatoes, always make twice as many you think you will need.)

9 Cheese is everything. I knew this at eight years old, eating brie for the first time in long grass at the side of a French road, and I know it now I am … um, older.

10 As Julian Barnes wisely notes in The Pedant in the Kitchen, most of us have too many cookbooks. You probably don’t need a new one, and you might also want to cull some of those you already own (Easy Recipes from the Kazakh Steppe; Aquafaba for Ninnies). My most loved and best used cookbooks are Roast Chicken and Other Stories by Simon Hopkinson and Margaret Costa’s Four Seasons Cookery Book. I’m also fond of Rowley Leigh’s No Place Like Home. His crab linguine is the best (NB involves butter). And no, I don’t read cookbooks in bed. Why would you want to go to sleep feeling hungry?

11 Cooking times: most things take longer than the recipe says, and those which don’t usually take less time. Cooking, like love, is about trusting your instincts. On the subject of trust, a sharp knife, preferably from Japan, is a beautiful thing. Put your faith in it, and all will be well.

12 Whatever people say, it’s basically a good thing that hummus is now ubiquitous.