All food has flavor, in varying degrees. Our palates recognize several different flavors — mainly sweet, salty, sour, and bitter — and we season things to enhance or emphasize these flavors or to create contrast among them.
We all have our own taste preferences (you might like sour food more than bitter) and thresholds (you might be sensitive to chiles, or not); part of learning to cook includes practicing how to use seasonings in the amounts, ratios, and combinations that work for you. Get in the habit of trying a bite of what you’re cooking after every addition of salt or other seasoning to see if you want more. (There are a few exceptions to this rule — you probably don’t want to taste raw poultry or eggs, for instance — but not many.) This single technique will turn you from a good cook into a great one.
What does ‘taste and adjust the seasoning’ mean?
This is perhaps the most important instruction in the book. When I say “taste and adjust the seasoning,” I mean add more salt and pepper, of course, plus more of anything else you might have used in the recipe, like spices, lemon juice, soy sauce, and so on. Add seasonings (especially salt) a little at a time, tasting frequently, so as not to overseason. If you overdo it, adding a little water may help dilute the saltiness. You’ll quickly get to a point where you can taste less frequently and eyeball the right amount of salt and other seasonings.
Generally, fats enhance and convey other flavors — a spoonful of oil doesn’t taste great on its own, but many, many flavors are improved by cooking them with fat. In many cases, you’ll heat oil or butter and add other flavorful ingredients to infuse the fat with flavor before adding meat, poultry, vegetables, grains, or noodles.