Unless you're an angler, why would you fillet your own fish? Two reasons: better quality, lower price. Buying whole is the best way to determine freshness and get the most from your purchase (the bones and scraps make great fish stock). Buy a fish with firm flesh that springs back when pressed; eyes should be shiny and clear; and it should smell like the ocean, not fish. Ask the fishmonger to scale and gut the fish, then use these techniques to fillet any kind of round fish, such as striped bass, shown here.
Kitchen Tip: Latex gloves will keep your hands from smelling fishy.