Make sure you have a clean flat surface and a good sharp knife. The top of an ice chest works for me! Wash as much of the fish slime off as you can as this makes the flounder easier to handle.Cut across the fish through the skin just behind the gills. This cut should go down to the bones, but not through them. We never cut through any bone when cleaning a flounder.Find the lateral line that runs down the middle of the side of the fish from the gills to the tail. This line roughly marks the backbone of the fish. Make a cut from the center of the gill cut down the side of the fish to the tail.Continue the T cut down to the bone. Your knife will find the backbone of the fish. Ideally, the cut should be right on top of and down to the backbone and must run all the way to the tail.Using the tip of the knife, begin by inserting it along the backbone and under the flesh. The knife tip needs to be very sharp. Use long strokes that run from the gill to the tail along the bones. This will begin removing one side of the fillet. Use your thumb to lift the filet from the backbones as you continue making long knife strokes.Continue the long knife strokes as you lift the fillet from the fish. These stokes will separate the fillet from the back bone, all the way to the dorsal fin of the flounder.Once the top piece is separated from the back bone, make the same stroking cuts to the bottom half. This will free two pieces of fillet from the backbone of the flounder. Remember to leave the two pieces attached to the fish near the tail.With the two halves of the fillets still attached to the tail of the flounder, we can begin removing the skin. Lay one filet to the back of the fish with the meat up and the skin down. Allow the skin that is still attached to the fish body to help you with this operation. Place your fingers on the small end of the fillet where it is attached to the fish. Lay you knife flat and begin a cut into the flesh and down to the skin. This is delicate and takes a little practice. Use a slight sawing motion as you push the knife away from you and under the flesh. Done properly, the fillet will be removed from the fish leaving nothing but skin.Finish the second fillet as you did the first. Use the fish to help you hold the skin and let your knife slip between the skin and flesh. Fish skin is tougher than flesh, so as long as you knife remains relatively flat, you should be able to master skinning in short order.Once you finish the dark side, turn the fish over and repeat all the steps. The fillets on the white side of the fish are much thinner than those on the dark side. Smaller flounder are difficult to handle when filleting the white side. Some anglers fillet the white side first. They feel that filleting the dark side first removes some structure that makes the white side harder to fillet. I understand their thoughts. I think I do the dark side first out of habit more than anything. Try both methods and see which one works for you.