Make your cut with the scales not against the scales, that is, run from head to tail on both sides of the fish. This saves your knife from rapid blunting. Scaling prior to filleting is even better for the life of your knife.
Use a sturdier/shorter boning type knife for bones(ribs) sharpened with less angle, to avoid rapid dulling of the blade. A longer more flexible knife is used for filleting the flesh of the fish, sharpened with a longer thinner shoulder of the blade.
A breaker/scimitar knife is perfect for steaking fish like mackerel, wahoo, black king, etc.
A skinning knife can be sharpened on one side only, using the dull side down, sharp side up.
Remove the oxygen from packaging bags that you put your fish in. Wrap in layers of newspaper to minimise freezer burn. Zip lock bags are very convenient for packaging fish fillets and easy to remove excess juice and air from the bags.