I nymph for salmon\steelhead from time to time.
I don't generally use a strike indicator, but when I do, I rig it like this:
Small\medium corkie
1inch of yarn
9 feet of 8-10lb leader
Flies - various egg patterns, glo bugs, stone flies, caddis, green rock worms, etc - depending on river\timing\conditions, etc
If the fly isn't weighted, just add a small spit shot 18inches up.
Thread leader through corkie, then back through again leaving a loop at the other end.
Put your yarn through this loop and cinch down firmly by grabbing the tag end and the leader - pulling a little yarn into the corky to make a snug fit.
To adjust for depth, just tug on the yarn to loosen it up, adjust length, then snug down again.
Casting isn't so bad - just open up your loops a little. Smaller corkies will have less wind resistance.
In smaller rivers and pocket water, distance usually isn't an issue.
Another method I prefer is to combine nymphing with a swing. In this situation I either use a non or slightly weighted fly and a sink tip to get my fly down. Cast upstream a little, then use various lind mending techniques to keep the fly low as it dead drifts past me. Then finish the drift by letting it swing a little and rise up to the surface. Let it hang for several seonds, then strip it in several feet before casting again. Takes will often be on the rise or hang.
If I don't want to use tips, I'll use tandum flies. You can take a heavier weighted fly as your lead fly, then tie on a smaller egg pattern or nymph for the dropper. Fish off a floating line with 9-12 foot slightly tappered leader. Keep your loops nice an open....
In all situations above - the key is in working\mending the line. The better feel and control you have - the more confidence you have that your fly is in the 'zone'. And the longer you are in the 'zone', well, you get the idea....