You can have the hottest-color lure in your area, but it won't do you any good if it's out of tune. Even a crank that ran well last week can be off this week simply from the weight of a thrashing fish, or perhaps you were overzealous with your pliers when removing a hook. To check your tuning, put the lure in the water and pay out a rod's length of line. Pull the rod forward as the boat moves. The lure should dive straight down. If it shears off to one side, bend the line-tie eye in the opposite direction of the way the lure is tracking with needle-nose pliers. The trick is to bend it slightly, readjusting until it runs true. Don't twist it like a pretzel, because you risk making the lure permanently un-tunable.