Nymphing should be done on the bottom of the river. You do not find
nymphs up in the water column. They will be found within the first 2-3
inches off the bottom if they get dislodged.

You generally don't want nymphs moving faster than the current so a
dead drift is usually your best approach. Not always, but usually.

The time to add movement to a nymph is when you want to imitate a
hatching insect. When you learn to swing a nymph, you can get enormous
strikes.

The other method is the dry-dropper other people have suggested. You
are imitating a hatching insect on its way to the surface. You don't
want the dropper to be too far below the surface, 18 to 24" max.

Fish are going to minimize their effort to maximize their food intake,
so fish the areas where fish are likely to be and that's just off the
bottom or just below the surface when they are taking emergers that are
trapped by the meniscus.

As always with fly fishing, the only rule is there are no rules.