I use a Vexilar and an Eskimo power auger. I can generally have a rough idea where the fish will hold on the type of lake, mesotrophic, oligotrophic, etc., based primarily on the depths I know will most likely hold adequate oxygen. I then combine that with a topographic lake map and determine search areas. I may bore as many as a 100 holes quickly looking with the Vexilar for fish. Once I find fish, I fish them to determine size, etc. I can generally determine what type of fish I'm looking at before dropping a line based on their location in the water column. I fish a tight line with a spring on the end of my rod. I generally do quite well and my freezer is usually well stocked. I fish a variety of ice flies I tie myself on nymph hooks using mostly cactus chennile or larva lace. I weight these with a lead wire underbody to get the performance I want in the water. Obviously with the Vexilar I can see my bait as well as the fish and I can see the fish approach the bait. If I see, for instance bluegills holding on the bottom, I will generally lower to them and then try to coax one to rise with the bait by jigging it and raising it slowly. My experience is if I can get a fish to rise he will generally take the bait. Once a fish moves up in the water column, I know he is interested and generally these fish are reluctant to see a bait escape. I generally tip my bait with spikes and then dip them in a bottle of grocery store anise oil.
Can't help you with locating fish since I don't know where you are located.