The single most important factor in catching early season muskies is warm water. The best and most obvious places to find warming water is in dark or stained water bays on the north end of lakes. Combine this with deep-water access and you've really located a hot prospect.
Food is the number one reason muskies invade the shallows.
They come looking for baitfish, and then hang around to spawn, if conditions are right. There are other features found inside shallow bays that make them appealing to foraging muskies. We've already mentioned warm water, but if that warm water arrives via a feeder creek, it's a bonus. Incoming current attracts baitfish. Warming bays also foster weed growth.