Involves: Colour Fill Layers and Selective Colouring
Steps: 6


I know some people prefer to have reasons given for a particular step so I've tried to give this, but most of the time I just play around until I get something I like.
Starting off with your picture, crop and edit to your liking. I'll leave the image at 300x200 for the purposes of this tutorial.

1. New Colour Fill Layer of 1a0758 (darkish blue) and set to Exclusion 100%

I like using blue exclusion layers as it makes the image look softer and gives the skin a nicer tone. For this colouring it needs to still be quite blue.
2. New Colour Fill Layer of fff002 (bright yellow) set to Soft Light 80%

I often start my images with these two steps and then play around with selective colouring, as it helps to bring colours out; especially the yellow layer.
3. Selective Color Layer
reds: -100 / +50 / 0 / 0
greens: +100 / -100 / -100 / 0
cyans: +100 / -100 / -100 / 0
blues: +100 / -100 / -100 / 0
magentas: +50 / +100 / -50 / 0

Before getting rid of the over-yellow-ness of the image, I pulled out some of the colourings.
4. Selective Color Layer
reds: -100 / -50 / +100 / 0
yellows: +100 / -50 / -100 / 0
greens: 0 / 0 / -100 / 0

I'm trying to make the image more red and green, so again I wanted to use selective colouring for these. And get rid of the yellow.
5. Selective Color Layer
reds: -100 / +50 / +50 / 0
yellows: +50 / +60 / 0 / 0

Again pulling out the reds, which seem overthetop at the moment. Also darkening the yellow in the image.
6. Duplicate base layer , bring to top, and set to Hard Light 100%

Finished!
As with any tutorial, when you use your own image the settings may have to be adjusted. So play around and see what is best.
Watch out for images with lots of red already in them.
Here's some examples of the different effect on different images (I've left the opacities and settings the same for comparison):




I hope someone finds this useful! ^_^