Drift fishing or bottom bouncing is by far the most popular technique for steelhead fishing. My first steelhead was hooked while drift fishing on the Elochoman River in southwest Washington. My Okie drifter was just completing its drift and was swinging towards the near shore, when suddenly my line went limp. Not knowing what was happening I began to reel in, and then noticed that my line was actually moving upstream. It took me awhile, but I finally realized that a fish had picked up my Okie and was swimming upriver. I reeled up the remaining slack and caught up with the fish. The fish turned and shot back downstream, finishing with a roll that threw my Okie, as I never set the hook into this first ever steelhead. That same year I hooked and landed several more winter steelhead on the Elochoman, finally becoming a successful steelheader.
Drift fishing was the only method I tried during my learning years, and I eventually felt that I could distinguish the difference between my lead bouncing along the bottom, and the subtle take of a steelhead. I seldom drift fish anymore, as I prefer float fishing or tossing spoons for steelhead, but a vast majority of steelhead fisherman still prefer this proven method over others.
Terminal tackle for drift fishing is rather simple. Tie a swivel on the end of your mainline, and attach pencil lead or a slinky. Add a leader with a drift bobber such as a Corky, Okie, Cheater or Steelhead Rag and you are set. You may choose to add a small piece of yarn to this setup, as this will add some contrast as well as help hold scent. The yarn will also help keep your hook in a steelheads mouth a little longer by hanging up in the teeth of the fish. This may be just what you need to feel the soft bite of a steelhead.
Any type of bait can be added to the basic corky and yarn setup. I've used roe, prawn meat, sandshrimp, squid, and nightcrawlers, and caught steelhead with all of them. The added scent and taste will help a steelhead find your rig in off colored water, and may cause the fish to hold onto your hook a little longer, giving you a better chance of feeling the bite and setting the hook. Although fresh bait can help, it is not necessary to hook steelhead, especially in fast water. In this situation the steelhead only has a few seconds to make a decision whether or not to take your presentation, so visual attraction is much more important than scent.
I won't go into much detail on colors as they will all catch fish. Matching the size of you drift bobber to the current water conditions should be a much more important decision. I believe proper presentation of your drift rig will make a much greater difference in your success. In my opinion most drift fisherman use too much weight when drift fishing. Your drift rig should move along at the same speed, or only slightly slower than the river current. Instead of your weight constantly banging the bottom, you should only feel a bump every few seconds. The exception to this rule is during periods of reduced visibility where a slower presentation is necessary to allow the steelhead see your offering. Successful drift fisherman are the ones that are constantly changing the amount of weight used to match the particular drift they are fishing. Proper presentation is a must to consistently hook steelhead.
Then take this information to the river with you and apply it. Don't be afraid to experiment with your drift gear, try different color and bait combinations until you find one that you have confidence in. As I've said before confidence is a very important factor for success in steelheading. If you are having trouble hooking steelhead on drift gear, get some books and gather as much information as you can about the subject.