Lengthens angling season. Teaches anglers ethical sport fishing. The fish you release today is your gift to another angler. Trout frequently swallow live baits more deeply. Consider replacing treble hooks with single hooks.
Single hooks are quicker and easier to remove.
Minimizing the time required to land a hooked fish reduces unnecessary stress. Avoid netting or even removing fish from the water if possible. Minimize handling of fish, especially the gills and soft underbelly. Moisten your hands before touching the fish. If you have to use a landing net, use one with a soft bag rather than hard nylon types.