My buddy told me that a plain live minnow is the best bait for catching spawning-run Walleyes. Are there certain conditions when this works best?

Using a simple live minnow is the often your best bet during the spawning run when the water is clear and cold.  To keep the minnow alive, hook it through both lips from the bottom up.  I’d suggest using a minnow that is approximately 2 to 4 inches long.  Your hook should be anywhere from a size one through four.  You’ll also want use a couple of split shot about 12 inches up the line.  When you cast, you’ll want to go across and slightly upstream.  Allow the bait to settle close to the bottom and then begin to slowly pump the retrieve.  Reel the line a couple of turns and then lift your rod allowing the bait to settle down again to the bottom.  Using this technique you won’t feel a big strike, instead the line will become heavy and will start to buck as the hook sets and the Walleye attempts to pull away from it.  When you’re fishing for Walleyes, don’t forget about the shallows.  When the spring waters start to warm up you can often catch large Walleyes around the weedbeds, reefs, rock piles and sunken timber in water with depths of just a couple of feet.