Start with the right equipment: an electric knife or sturdy fillet knife and a fish cleaning or heavy-duty gardening glove.
Lay the fish on one side. Place knife blade under front fin and cut at angle toward the head and downward, stopping at the backbone.
Turn the knife so the blade runs parallel to the spine and cut slowly and carefully, sliding the knife along the backbone until you reach right above the tail.
Pull fillet away from the body of the fish, flipping it away from the head. At this point you can simply cut the fillet away from the tail and leave the skin on for grilling.
To remove the skin, place knife at the point where the fillet is still attached to the tail and slide it under the meat along the skin. Keep the blade flat and parallel to the countertop, being careful not to cut deeply into the meat.
Many people remove the rib cage and belly because though there is some meat, it is mostly bones. To remove the rib cage and belly portion, cut along the vein from the head end to the back edge of the rib cage.
Then, cut from the vein to the edge of the fillet. The end result is a skinless, boneless fillet ready for cooking!