They don't really eat much when they return. Mostly a reaction bite. Most steelhead tyers talk a lot about "triggers."
I have been told the following by multiple guides.
1. You have to put the fly in front of them, a foot or two off the bottom, except when they are hitting on top.
2. Wet fly swing, or Greased line, or indicator nymph.
3. The lower the water, the smaller and duller the fly.
4. If they swirl at your fly, try a smaller drab fly.
5. You need two patterns, a black wing or a white wing. A dark fly, and a bright one. In different sizes.
6. The fly you use doesn't matter. Conversely, try different styles to give them a different look.
7. It is a mystery.
8. These magnificent fish deserve aesthetically beautiful flies, or try a Wooly Bugger or an egg pattern
9. Try pink, orange or black. Or purple...or
10. The fishing used to be great
It is a weird subculture