I would definitely say to a newbie that it's not a bad idea to hone your skills at a hatchery meat hole, like spots on the Cowlitz, Lewis, or Skykomish.

Once you know how to cast well, and how to detect strikes, now you have to go out and actually learn the real art of steelheading, which is impossible in the meat holes. I have been acquainted with lots of fishermen who equate catching a lot of fish in those spots with being a good steelheader, which is only true so long as they stay in those meat holes. Give them a river that requires some skills and their productivity drops markedly.

Reading water, tailoring gear to the specifics of the water you are fishing, finding your own spots, etc., etc. Most have been listed above.

Here's one that wasn't mentioned yet. While I agree with Dave's point about lighter line and lures, that doesn't mean use six pound test when there is a full river with 12" of visibility.

I find light line to be most important in attractively presenting the bait, not necessarily because steelhead are leader shy. I only use 8# leaders if the water is over 30" or so of vis, other than that I stick with ten, even bumping up to twelve if the water is really up.

When I'm fishing unlimited vis and small baits, I find the lighter line to be more important for properly delivering a smaller bait, rather than trying to make my leader invisible.

Fish on...

Todd.