One of the most important things a steelhead angler needs to learn is the run timing of the rivers they fish. Some good ways to do this is watching for concentrations of other anglers, contacting local hatcheries for return information, reading fishing articles, and check several Websites for updated information on Steelhead returns. Also, successful steelhead angling depends primarily on river levels or flow rates, and water clarity water temperature does play a part also however I do not believe this is as important as water color. You can find this information on the USGS website for almost all rivers and this information is kept current as to flows and anticipated flows.If you head out after a heavy rain, with a few exceptions you will be wasting your time. Clear water is good, green or slightly colored water is even better, so call someone if you can and find out how the rivers and fishing are; most of your locale tackle shops will be able to provide you some information.
Over the years I have learned that line size, hook size and weight affect the drift angle and your presentation of the bait which plays a big role in increasing the percentage of strikes. You could write a book about each one of these items but if you remember to decrease the size of each of the above mentioned items you will be on the right tract. I have learned that when drift fishing from a boat, different styles of boats react differently in the current, this has a direct affect on the way the angler is able to drift the bait along the bottom.
Small spinners, drifted yarn flies, and float-fished roe bags, or shrimp are deadly on most steelhead rivers, so are black or brown nymph imitations. Sometimes under the right conditions (I wish I could tell you what these conditions are but I never know when they prefer these) steelhead will go crazy for medium-sized spoons and/or spinners. You cast them quartering upstream, let them sink almost to the bottom, and start a slow retrieve when the current starts to swings it towards the bank.
During the later steelhead season fly anglers that are skilled at nymph fishing can do very well in many of the runs. You can fly fish with less knowledge about bugs as it is more about presentation with the steelhead the which fly you should be using. You should be ready for cold water fishing as the water temps can be in the mid 30 degree range but for those who enjoy this type of fishing it can be extremely satisfying. Try swinging streamers made of rabbit or marabou if a steelhead is out there they should produce a strike and for what ever reason they seem to hit this type of fly pretty hard.