ok- this isn't as glamorus as anything Dave does BUT
to cheat:
add a layer above your photo and fill it with a color and reduce the opacity to your liking
then select where you want the color to stay with the magic wand, lasso, marquee tool, etc.
then click Select>Inverse
click delete
or you can erase away what you don't want
this is just one way- there are umteen different ways to achieve something
HTH