Use windows to limit keys to a specific are of an image so they don't pick up similar colors in another part of the frame. Example - Key a sky to make it more vivid, but someone is wearing blue....
Use soft circle windows to brighten up or darken faces as needed, especially to compensate for dark or aggressive looks. Face windows/vignettes are very common in coloring, and can be a great tool in your workflow. This may seems like...
In Apple Color secondaries, there are three views for window or key selections - the final output, isolated color, & the matte. The matte view is probably the most useful of these for fine tuning keys because you can see...
Key Tolerance vs. Key Blur - Tolerance ramps down the colors that are keyed instead of a hard stop. Blur softens the matte. Use tolerance to fine-tune a key that won't pick up something fully. Use key blur to soften...
Don't just rely on the eyedropper to pull your keys. usually it'll do a pretty crappy job. be sure to hit those qualifiers! Qualifiers are the hue, saturation and luminance sliders that let you fine-tune keys with tolerance, softness etc....