Catching fish on a fly is simply about ONE thing. The fisherman must Present the fly so that it looks like nothing is attached to it, and they will eat it. If you present a cigarette butt properly, a fish will eat it.
It doesn’t matter what rod, reel. line, or fly that you use. Too many fly fishermen emphasize matching the hatch. The fact is that when fish are eating, they are hungry and will eat what looks good and natural. 
When a fish is facing upstream and looking at hundreds of bits of potential food items, why do they just pick one? It could be that they only take what’s close, what looks crippled, timing between chews, or there is something different about a morsel.
When you go to a wedding and it’s time to eat cake, the entire cake is cut up and presented on the buffet. How do you pick which piece to take? Maybe it’s the biggest, smallest, has icing on 2 sides, or has an icing flower on it. My point is that you don’t pick a piece of cake that looks like every other piece. It’s human nature to pick something different that gets your attention.
I have seen fly fishermen go for hours without catching fish, while others are putting on a clinic. Stubborn fly guys hate to admit that they might be doing something wrong. Their casting may be perfect, but they are fishing in the wrong place. They may have the perfect fly but are fishing it at the wrong time. They are in the right spot but are fishing in the wrong direction.
The thing that I enjoy about fly fishing is that I will never master it. There is always something new to learn. Be open minded and embrace what you are doing wrong. Ask questions and become a student of the sport.
Presentation may be just one thing, but it takes hundreds of things to get the one thing correctly. Presentation involves casting, reading the water, fly choice, leader length and knots, clothing, distance, position, approach, retrieve, and so on. It’s never just one thing! BUT, if you get everything else correct, the proper presentation will reward you with a fish.
Lefty Kreh was the best fly fisherman that I know of. His books, videos, and stories are excellent. If you want to own just one fly fishing book, buy his book called “Presenting the Fly”. This book is loaded with specific tips and tricks to make better presentations and catch more fish. Over the next few weeks, I will highlight some of Lefty’s tips and tricks!
Montana Grant
Hook up with Montana Grant on his Facebook Group at Montana Fishing For Fun.