If you hook one: landing and releasing gently
This is a lesson I probably should have taught earlier, but I wanted you to have the cast and the drift established first. Now we address the welcome problem: a fish is genuinely on your line. What follows.
Most beginners lose or injure fish in the same small set of ways, and all of them are correctable with roughly ten minutes of practice and some patience.
The moment it happens
You will feel a tug, or your line will simply stop and behave oddly. Your instinct will be to yank the rod straight up over your head as if spiking a volleyball. Do not do that. Lift the rod tip smoothly, not with a jerk, just enough to feel the fish and keep the line tight. If the fish runs, let it. The bend in your rod is doing the work, not your arms.
Keep the rod tip up throughout. This is the single instruction I repeat most often on the bank, and I will state the reason: a bent rod tires the fish gently, whereas a straight line to a flat rod either snaps or lets the fish throw the hook. Keep that tip up as though reaching for the sky, and let the rod do the fighting.
Do not reel frantically. Reel in the slack as the fish approaches; stop reeling and let the rod bend when it pulls away again. It is a conversation, not a tug of war.
Getting it close enough to release
A net is not required for this class, though if you have one it makes the process easier and gentler on the fish. If you do not, that is also fine.
Walk the fish toward slower, shallower water near the bank where possible, rather than horsing it straight in through the current. Once it is close and mostly tired (you will see it stop fighting so hard, and it will tip onto its side), that is your moment.
Wet your hands before touching the fish. This matters more than people assume: dry hands remove the slime coating that protects the fish from infection, so dunk your hand in the river first. Then, if you are removing the hook, do it quickly, with pliers or your fingers, backing the hook out gently along the path it entered.
This is where barbless hooks prove their value, which is my one mildly firm opinion, and I will repeat it as often as this class permits. A barbless hook comes out clean and fast, so the fish spends less time out of the water and under less stress. I pinch every barb down before I leave the house. It takes five seconds with a pair of pliers. No exceptions on this one.
Where you can, keep the fish in the water the entire time, or lift it for two seconds at most for a look, then return it immediately. Point it upstream into the current, hold it gently around the body (not squeezing the belly), and let it swim off on its own schedule. Do not toss it. Do not force it. It will indicate when it is ready.
Where NOT to put your feet
Throughout all of this you are likely moving around in the river, and I want to slow down here, because this is the part people skip past.
My neighbor Bradley borrowed a pair of waders from me a while back, a good fellow with more confidence than caution on some days, and he stepped backward while playing a fish directly into a hole in the riverbed he never saw. In to the chest. Freezing water, current pulling at him, and it happened in roughly half a second. He was fine, we got him out and dried off and eventually laughing about it, but it rattled him and it rattled me.
The Provo appears calm from the bank. It is colder and more forceful than it looks, every single time, without exception. So when you chase a fish toward the bank or wade out slightly to reach it, move slowly, feel with your feet before committing your weight, and do not step backward without looking first. If you are fishing from the bank in old shoes, as I generally recommend for beginners anyway, this is less of a concern, and that is one more reason I favor that setup for people just starting out.
Practice this at home, in part
You cannot practice landing a fish in your backyard, obviously, but you can practice the motion. Tie on a fly, with no hook-point concern since you will pinch the barb regardless, and practice lifting the rod tip smoothly and slowly rather than yanking. Get that motion into your hands before you are performing it with an actual fish on the line and your pulse elevated.
Before next time
Simply rehearse the sequence once in your head before you are on the water: tip up, let it run, walk it to the shallows, wet hands, quick release. You need not memorize it word for word. You will be surprised how much returns the moment it is real.