A contrarian thought -- while I agree that color and size are critical components but to me choosing the ideal material comes ahead of those two.

For example consider the tail of a typical jig -- will the tail be marabou or hackle fibers or craft fur or crystal flash or rubber or something totally different like kip tail? All are great options but each has its unique character that you have to consider. I like marabou for its movement but there are times when it has too much action that does not match the fishes mood and might be spurned.

For the body chenille is very common selection and it is known to be a staple of our sport but I rarely use it- I prefer to dub my bodies with flash or sparkle fibers to get an overall minnow look that chenille just cannot match. What minnow or insect looks like a some of the chenille combos out there? But those crazy chenille colors put a sore jaw on many fish all across our fine land because it does enough to suggest an edible food source.

To each our own of course but for me I think through the materials first then size then color are my concerns.

Great question!