RTF,
I've had no luck catching the fish that are cruising around. Try creeping up to the pool and observing for a few moments from a hidden location (seriously!). Look all along the shoreline for tailing fish. If you see a slow moving or stationary trail of bubbles, or if the water looks a little muddy in one spot, take a closer look. The fish are EXTREMELY hard to see at times, especially when they are near the bottom. Add some shadows and a little riffle and they're invisible. If you don't have polarized glasses it's even harder to see them. If you spot a fish with its nose on the bottom, that's the one to target.
When you see a feeding fish, stay hidden as best as you can while approaching and stay low while casting. If the fish is creeping along, try to get to a spot where the fish will come to you. When you cast to a fish, try not to let the flyline land on top of the fish. Even the shadow from the line may spook them. In fact, I think that even the knots in the leader (especially loop-to-loop knots), or the leader itself may spook them. You want the fly to land quietly and sink to the bottom just ahead of the fish. If the fish is moving, you can sometimes cast well ahead of it and move the fly into position, then wait for the fish to get near the fly. If casting room is tight, try roll casts. That's good practice too! I find that it's hard to make a regular cast when I'm crouched down anyway, although my roll casts don't go very far and it gets frustrating when the fish are just out of range. A heavier rod and line may help increase your roll casting range.
When you think the fly is right near the fish's nose, give a slow, short pull (1 - 2") and watch the fish and the end of the fly line to see if you can detect a take. If you can actually see the fly that's even better. You probably won't feel the take, but you may see the fish flare its lips or see the end of the fly line move slightly. You may even be lucky enough to see the fish eat the fly. If you can't see your fly or the fish's lips, watch for the fish to make a short, quick move towards the spot where you think your fly is. Sometimes you literally have to guess when to set the hook. A couple of times when I've hooked up, I wondered if the fish really ate the fly or if I just foul hooked the fish, but the fly has always been inside the fish's mouth!
If the fish doesn't take the fly, be careful when you pull the line in and prepare for another cast. Sometimes you can carefully move the fly away from the fish and then try again, but you may need to let the fish move well away from the fly before making a new cast.
As for flies, I've had tremendous success with a #8 brown woolly bugger, but the fish in your area may not want that. You may need to try a smaller nymph pattern. Whatever works for trout in that spot would probably work for carp as well. Try to see what kind of food is in the water and match that. Some people swear by berry flies. If there are berry bushes or trees along the river then that may be the ticket. The few times that I've tried berry flies it was more of a random s**t-luck kind of thing. I had to put the "fly" in the fish's path, then let it sit motionless on the bottom and hope that the fish sucked it in by accident. It actually worked twice!
Good luck, and let us know how you do!
Q