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 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.
To increase detail in landscape shots, boost the mid-tone contrast. Copy the background layer with Control/Command + J, and then click on Filter → Convert for Smart Filters in the menu. Pass and enter a radius of 3 pixels. Change the blending mode to “Overlay” and double-click the layer next to its name to open the “Layer Style” window.
For the first gradient, “This Layer,” split the sliders by holding the Alt/ Option key and trim the layer effect to the “50/100” and “150/200” ranges. As soon as you move the sliders, you’ll see where those numbers are. This increases contrast only for the mid-tones. Double-click the “High Pass” filter in the layer palette to bring the dialog box up again in order to adjust the radius to your liking.