Go to the Layer menu, and then New Adjustment Layer → Hue/Saturation,
and set the blending mode to “Soft Light” and check “Colorize.” Use the
Hue, Saturation and Lightness sliders to control the color: for a cool
look, for example, set the hue at 210, the saturation at 50 and the
lightness at 10; for a warm look, set the hue at 30, the saturation at
30 and the lightness at 5.
Here is Hue/Saturation and Color Fill.
Alternatively,
you could use several color layers. Create them from the layer palette
with the “New Fill/Adjustment Layer” button. Choose a color, then set
the blending mode to “Vivid Light.” Reduce the opacity to about 12%, and
invert the layer mask with Control/Command + I. Paint in
the colored light with a big brush and white color. This works
especially well for the lighting in portraits that have a textured
background.
Here’s the Color Look with an Adjustment Layer.