Tip: The Golden Rule of Filleting Fish
If there's one thing you need to remember when filleting a fish, Chef Stone says, "It is imperative to use a long, thin sharp knife when filleting fish. If you fillet fish often enough, you might want to invest in a knife designed specifically for filleting. A sharp knife means that it glides through the fish with easy precision — a dull knife will only hack away at the flesh." Look for something like the Masamoto VG to do the trick.
In terms of tricks, Chef Stone says it is best to refrain from taking the first side (fillet) completely off. Leaving it on the body will prevent the fish from sagging when you go to cut the other side. After you have removed the second fillet completely, simply turn the fish back over and remove the remaining fillet.
And most importantly, don't waste! The fish can be used to make a rich and tasty homemade fish stock. "Fish stock imparts beautiful flavor and moisture to fish risottos, pastas, stews (like bouillabaisse), and soups," says Chef Stone.