The eyes of a fish should appear natural. That means they are convex, not concave, and should still have an oval or round shape. The eyes generally should be clear, not milky. The biggest mishap, LaFray says, in preparing fish is overcooking, which makes it dry and tough. If you do that a few times, she says, you won't be buying fish anymore.
Some fish fillets come with the skin on, which many people find unappetizing.
If so, ask that the skin be removed when you buy it or take it off after cooking. As a general rule, fish cooked on direct heat require 10 minutes per inch of thickness. Baking will take longer, and you should follow the instructions in a recipe until you get a feel for the time. Fish is done when it is opaque and flakes easily at the touch of a knife or fork. Armed with LaFray's insight and her cookbook, we returned on our own to Save on Seafood a few days later to buy fish for that night's taste test.