Choose fish like trout, salmon, catfish, bass. Larger fish are easier to fillet than smaller fish. Think of fish as slabs of neat connected in the middle by a backbone, and ribs. Start by cutting off the yead, just behind the gill plate, angling toaeard the back of the head. This exposes the spine. Remove the dorsal, snd ventral fins by cutting just deep enough and cutting from the head towards the tail. Use a very sharp, thin knife for the job. Start the fillet by cutting along the backbone, again from head to tail, and at an angle toward the belly, sliding the knife edge along the rib bones. The entire side slab will be removed, leaving the uneanted parts behind. Repeat with the other side. When the meat slabs are removed, throw away the discarded parts, and wash cleaning area. Lay the fillets skin side dow. Starting at the tail end, slide your fillet between the flesh, and skin. Rock the fillet gently from side to side, while pushing the cuttig edge forward until all of the skin is removed. For salmon, trout, char, and whitefish, skinning isn't necessary.
Part of wht frightens people is the idea of cutting themselves. Gloves can be purchased that are designed to protect against cuts. They also make it easier to hold the slippery fish.
I hope this helps.
Seeeeya; Chief Longwind of the North