I fish in a dirty river and the bluegill really go for anything with a splash of bright yellow. Good luck!

Having "flash" is critical as well. Try including metallic flakes in your lures. These tend to work best if the flash is in sharp contrast to the color of the lure (like a dark lure with bright metalic flash). Stephsgobait's suggestion about bright yellow is a good one too!

try using an small bait with an spinnerbait blade on the tail, an tail spin, and these will work for the bigger bluegills and even small bass and pickerel