I go with the color of the water. In ultra clear water use the trout colored ones [I'm cheep,so I use the $2.00 Renegade brand at Wal-mart] In stained water I use the crawfish color and in really dark water the dark blue. If you can't see a foot down, get a dark one that rattles.
Rule to remember the darker the water the darker the lure. Same goes with the sky. At night use black.
Bill