You often want to set the lure so it's just barely ticking the bottom. As for finding walleyes this time of year, look in the basin, not real far from rivers and other spawning areas they used in spring. Good electronics like an Apelco 530, which has the added benefit of GPS will help you pick out walleye bumps on the bottom and let you drop icons where you see fish. You can then use the unit's plot trail to duplicate your trolling passes over the fish. Fall is the best time to catch some real horses while out walleye trolling as the cold water triggers these fish into bulking up for the long winter and the rigors of the spawn.
Big water is the best place to do it.
First, find the fish and then put something in front of them that triggers the strike. Despite cold temperatures, you're on your way to the hottest action of the year.