When stalking a trout you need to get down to the selected individual fish fast! Simplicity is the key when stalking, use a weighted Black or Red or Olive nymph that gets down pretty fast and can be fished as deep as you need; add a smooth profile plus an exciting tail for extra trigger points. Fish take advantage of natural cover, bank, reeds and overhanging bush/trees are prime spots. Be discrete in your approach, if you can see them they can see you.
To be successful, when you spot a fish, stop; relax and watch him for a while. Don’t hurry! From watching you may decide to catapult your stalking bug in front of the trout and induce the take by twitching the fly.
A weighted nymph gets down pretty fast and can be fished as deep as you need.