How do you ';shade'; with Photoshop?

I want to give the appearance of a darker tan on a picture I'm editing. How can I do this?How do you ';shade'; with Photoshop?
use the color replace tool and set the color to whatever shade you want. It's under the same pallette as the paint brush tool.





Or if you just need it darker try the Burn Tool it will darken either the highlTight, midlights, or shadows.....