I'll assume you're talking southern Michigan and the inland lakes just for ease of discussion. Once opening day arrives (April 26th) you'll find post-spawn fishing on most lakes. This means that there will be fish deep and shallow with patterns usually not developing until the water temps get into the mid-60's. New weeds attract baitfish and muskies when they're in the mood to eat but this is dictated by the forage offered in a lake sometimes they never need to go shallow for food. Often the most consistent fishing will be on sunny/warm/calm days until the water temps get into the 60's. Covering all good structure from shallow to deep will help you locate fish and provide some insight on where the majority of the fish are hanging on that day.

There's no magic lure and anything will work provided it covers the depth intended on the structure efficiently. A general rule, some people use, is smaller in spring and increasing as the season progresses. While this can be true at times it isn't always true and big lures will still work in the spring. It really has more to do with depth and speed control than the size, color or make/model of lure.