Find the forage first
Turn over a rock. Look in the shallows at night. Check the stomach of a fish you are keeping. Whatever is abundant is what the predators are eating.
Match size before color
A predator keyed on two inch shad will refuse a five inch swimbait in the same color. Profile size is the first filter, color is the last.
Seasonal shifts
Crawfish dominate in spring when they molt. Baitfish dominate in fall when they school. Fish the forage calendar, not the tackle catalog.