Making of: All the Time in the World

These are very cool. I'm a noob at photo manipulation so you've inspired me that photo manipulation can create some awesome things.

I just wondered in your steps, what kind of settings do you change to change the color to fit your BG and match the colors in the rest of your image? There's a lot, from hue, saturation, brightness, contrast, levels...
That's where I have a lot of trouble, even a link to how to do it is fine.