How do I change the contrast on a Dell - Asus laptop computer?

I think the colours on my laptop are a bit unsharp and boring, so I would like to make them crisper and sharper - but how do I do that?
I can't find a contrast button on my keyboard, and I can't seem to enter any adjust windows on the computer itself.

My computer keyboard looks like this, by the way:

The keyboard.

If you don't have a hardware method, you can always try this
Calibrate your display