Apple Color

Watch these 2 tutorials, they are very similar, but use different techniques to selectively change colors within your video clips using the secondaries room in Color and adjusting saturation (a.k.a Sin City Effect). Primaries are for an overall color look, secondaries are for selective color looks. You can have multiple secondaries to achieve a look in Color.

Using saturation curves

Using color key matte

Tracking with a vignette