Rick is right about a yellow boa yarn leech working well for crappies! Unweighted chartreuse Woolly Buggers, too.
One of my most consistent producers in the past couple of years has been a chartreuse 1/80 oz microjig suspended about 18" beneath an indicator. Your magic depth may vary.
My favorite strike indicators for this lately have been the Fish Pimp strike indicators...original size, yellow color.
http://www.fishpimpco.com/product/fish-pimp-original/