When building flies to swing for steelhead, keep in mind how big in the water you want the fly to be.
For big profile flies, wrap a ball of chenille or dubbing behind your hackle to help the fibers stand up against the current. You want enough material that the fly doesn’t compress. Streamlined flies don’t need the support. Tie up both varieties to use in different conditions.
Regardless of the profile you’re tying at the moment, use less material than you think you need. You want your fly very sparse so it can sink through the water column. Too much material and it’ll never get down, and the movement of your oh-so-fancy natural materials will be limited with overdressing!