One of my favorite methods especially on rivers is dragging a light jig downstream. This method has saved the day on many occasions especially when the water temperature is in the high 30's and low 40's. Use 8 lb test line and jigs up to 1/8th ounce. Any heavier and they are more prone to snags.
Troll or drift downstream at the same speed as the current or a tad faster. This will allow your jig to get down even in deep water. I've caught walleyes in 15 to 20 feet of water using an eighth ounce jig hundreds of times. The light jig ticking along the bottom is irresistible to aggressive and non-aggressive eyes.
Remember river fish stay on the bottom because the current (because of friction) is weaker than it is a foot off the bottom and of course, they have to face upstream.