Going to add to various points already made, because they are good ones.
Depending where you live seafood is definitely one of those options where you get what you pay for. Here in Colorado, we’re about as far from anything resembling fresh seafood as you’re likely to get (other than some river trout, which, meh) - so in general, if I want fish to be the main focus it’s going to be purchased at Whole Paycheck or the like. Grocery store options are fine for seafood alfredo, strongly flavored marinades, or fried options - which are good choices if you want to dip a toe into seafood cooking with more insurance.
Cooking - cook it until it’s almost done, and let carryover finish it. Just like a good steak (by most tastes, not all) once it’s overcooked it can get tough and loses flavor. Two options for cooking not explicitly mentioned - you can poach it at your target temperature for quite a long time without much loss of quality. If you poach at high temps, same as cooking with dry heat. (I know sous vide has been mentioned, and this is basically a poor man’s sous vide option without an agitator, but if you don’t already have the equipment…).
For whole fish, one option I love is a salt crust! If you haven’t heard about it, you take a good size whole fish (2-3 lb red snapper as example), and one or two boxes of Kosher salt (depending on size of fish), mix salt with water and egg white, and make the salt mixture into a paste. Put a solid bed on an over safe pan, place gutted fish on salt with cavity stuffed with aromatics [lemon and orange slices, fresh herbage (I like cilantro), and other seasonings (garlic, scallions, shallots, what have you)], mound more of the salt mixture over to seal, after placing a probe thermometer in the deepest meat of the fish.
Throw whole thing in a hot over until internal temp matches cooking temp for doneness of selected fish (ALLOWING FOR CARRYOVER). Take out of over, gently crack salt crust which will be hard with a meat mallet / hammer, pick off chunks, lift out fish and brush off salt. Will be delicious, moist, and properly seasoned.
ETA - I don’t have any seafood specific cookbooks, because my wife, before she went vegetarian didn’t like fish AT ALL, but I would recommend any of Alton Brown’s basic cookbooks, in that he does a good job of spelling out the basics and techniques, and most of the details are down to practice and personal preference. But Jamie Oliver will get you the basics as well as linked upthread.