I took stats of lost fish in my years of guiding. If your letting the fish get below you by more than a 45 degree angle downstream (as in, your upstream of the fish, it's downstream from you, and your applying a lot of presure to bring it back towards you against the current), your going to lose approx 90% of the fish you hook while nymphing. This does not apply to streamer fish, becuase there normally hooked below your feet and if they stay on for more than the first 10 seconds, there usually going to get landed...
So for nymph fish, I always told guys as soon as you hook up, get your butt to shore, and be prepared to run down with your fish, keeping it right in front of you instead of letting it get downstream of you... if guys did that the lost fish percentage decreased substantially... like only 35% got off. I hope this helps. You'll use a lot of bank, sometimes 500 yards when fighting fish this way, BUT.... when your holding a 25 incher instead of cussing at the one that got away, it'll be worth every step back to the hole you were in when you hooked it