One of the ways I change color is by Image/Adjust/Replace color.
1-have your picture open
2-go to Image/Adjust/Replace color
3-w/ your cursor (which now is an eyedropper), select a color within the image that you'd like to replace
4-now move the 'fuzziness' slider, which controls how large or small of an area within the image that will be changed. This is also where you can change the color (hue) or the saturation and lightness.
There are multiple ways to do things in photoshop, but other than making a detailed path or selection, I've found this to be a good option.
hope this helps...