Follow the contours you see on the bottom. Try to stay on the edge of the river channel, on the side of a ridge, or along some other feature. Another way to get lures down to the fish is to use steel line on heavy tackle. Such a setup is tough enough to drag the bottom. The single best lure is a J-13 broken back Rapala.
Colors vary somewhat.
Silver and black are usually best. In the fall, when kokanee are spawning, orange Rapalas with gold bellies can be effective. Chartreuse can be good when other colors aren't working. Big flatfish and spoons may also be effective. A deep-diving crankbait can be effective at times.