I like “sight-nymphing” to trout. It’s a specialized style of nymphing that some Rocky Mountain tailwater fly fishers have elevated to an art form. To my way of thinking it combines the most exciting elements of dry fly fishing and nymphing.
Accomplished sight-nymphers all agree that the best strike indicator is the trout itself. Practice by watching a trout feeding on actual nymphs, midge pupa or larvae. If you see anything close to the same feeding behavior when your nymph imitation drifts close to the trout it’s time to set the hook.