Colour Correction can be used for a range of things, If a photo is to under exposed, Has to many shadows and you want to bring some of the details forward, this is a quick and easy way to fix an image.
Firstly, I had to find an image on which it was under exposed, and I thought it would be worth fixing up.
Next I bought the image into photoshop and started to tinker with it, I started with adjusting the levels of the image which I just bought into photoshop by hitting Command + L (For Macs) or Control + L (For Windows).
This brings up the level adjuster and allows you to work with either the whole RGB colour scale or each individual colours (Red, Green and Blue)
Adjusting individual colours can give you a more bizarre feel by using too much green or any other colour, But using the default White and Black Balance will allow you to get rid of dark shadows.
REMEMBER! The more times you do this and confirm the change the more you will damage the image and have to start over! (I had trouble with this first time starting out)
This is what I have accomplished within this explanation;
These are some other colour correction tutorials on which you can accomplish this same effect;
