A few flies I trust (and why I ask the fly shop the rest)
This module has concentrated entirely on water — seams, riffles, and holding positions — and that sequence was deliberate. Beginners tend to invert the priorities. They want the exact fly first, as though it were a password, when in fact the water is the component that catches fish.
That said, you do need something on the end of the line. So we will address flies directly, including the areas where my own knowledge is limited.
First, the operative principle
A beginner who can read water and is fishing an adequate fly will outfish an angler with an extensive fly box casting into dead water. I will keep stating this until you accept it. The fly matters; the water matters more. If you retain only one point today, retain that one.
The short list I actually trust
I am not an entomologist, and I will not pretend otherwise. Matching the hatch — determining precisely which insect is emerging on a given afternoon — is a genuine discipline, and some anglers are excellent at it. I mostly estimate and get lucky. Over roughly twelve years, however, I have settled on a small set of flies that have caught enough fish on the Provo to justify their place in the box.
An Adams, size 14 or 16. My default dry fly. It does not imitate one specific insect; it presents a general suggestion of an insect, and trout accept it. When something is rising and I cannot identify it, I start here.
A Pheasant Tail nymph, size 16 or 18. This does most of the work below the surface. Trout feed subsurface far more than they feed on top, whatever the magazine photographs suggest. If nothing is rising, this is likely in the water.
A small Prince nymph. A similar concept, somewhat flashier. I prefer it in faster, riffled water, where a fish needs to register the fly quickly.
A Woolly Bugger, olive or black. A larger streamer-style fly, suited to covering water without matching anything precisely. It withstands hard use, which on some days is a relief.
Four flies. That is genuinely most of what matters in my box. The remainder are items I bought because they looked appealing in the shop.
Why I still ask the fly shop
Here is my limitation, stated plainly: I am poor at insect identification. I cannot reliably tell you what is hatching on a given day, and the accurate answer shifts with the season and even the week. So when I reach the river and activity is low, or I am somewhere unfamiliar, I stop at a fly shop and ask what is currently producing. It is not pride; I simply know my limits. Five minutes with someone who fished that stretch yesterday is worth more than twenty minutes of my own squinting at the water.
You should do the same. It is not cheating; it is using an available resource.
Practical preparation at home
Before your next trip, spend ten minutes examining flies — in a shop bin or online — and get comfortable with the size numbering. Higher number, smaller fly. A size 18 is very small; a size 6 is large enough to stuff a burrito with. You do not need to memorize insect names. You need to not be confused by the numbers when someone hands you a fly and says "try a 16."
Also practice tying your clinch knot onto an actual fly at the kitchen table, not a bare hook. The eye on a real fly is smaller and more difficult, and your fingers need practice on the real object, particularly if your eyesight has declined (mine has).
This recalls my first trip to the river. A neighbor took me up, I fished for three hours, and I caught nothing. Zero. I returned home and Tricia asked how it went; I said, "I didn't catch anything and I want to go back tomorrow." She looked at me as though I had misplaced something. I had not landed a single fish and still could not wait to return. I mention this because the fly — the specific names, all of it — matters less than you expect on that first day. You will fish an Adams or a Pheasant Tail, possibly catch nothing, and still have an excellent afternoon. That counts as a good day. It genuinely does.
Before next time: select one dry fly and one nymph from the list above, actually acquire or borrow them, and get them in your hand so they cease to be abstract.