How To Do This Kind Of Intense Colouring/Contrast?

I know this isn't a photography community, but I didn't know where else to ask :( And since you guys are all into colouring, I was hoping someone could answer my question.

Something I noticed is that photographers often seem to use a high contrast or saturation thing. Makes pics look very intense instead of flat. Often it has a blue or greenish kind of tone to it.

I've been trying to imitate this effect in my graphics programs for a long time, but no luck :(

Can anyone help?



Examples of what I would like to do:





Both photo's by the lovely and extremely talented Ale from Laertes.



By the always kickass Jenn.