Long time fishing writer for Sports Afield magazine, Jason Lucas, often called the father of modern black bass fishing, had some interesting tricks he used while fly fishing as well with other styles of fishing.
In his book, "The Black Bass" he describes some very successful techniques which I have long since proven to myself for bass fishing and have adapted to trout fishing.
One such technique is called " banjo stringin' " the fish. While Lucas describes this technique as a way to fish from a boat, it also works for other modes of fishing conveyance, such as wading.
When a large fish (or smaller) makes a heads down run for the brush, deep water structure, weed beds, or other areas likely to foul the line, or when the fish heads straight at you or your boat in an attempt to do the same, you simply have only to put some bow in the rod with some pressure and pluck the line, "twang, twang, twang", to get the fish to stop dead in its tracks or change direction altogether. The vibration is transmitted to the fish via the line and momentarily "confuses" the fish.
I have on more than occasion used this "trick" on big browns in deeper water pools and runs and it works. Of course, this maneuver was invented for deep and "big" water, however, it will also work in most situations when there is a chance that the "big one" you hook, won't be "the big one that got away".
Blue skies, warm gentle winds, and trout filled waters to all!