Its quite short and simple , but you do need adobe photoshop. Basicaly all you do while you are in the program is load up the pic then hit :
Shift + Ctrl + L
This is the hotkey combo to auto adjust all the levels of the picture so they appear more as the real thing. It gets rid of unwanted tints in a picture like say if something turns out yellowish . It also enhances the brightness and contrast so pictures appear chrisp and life like.
Anyhow here are some sample pics of the adjusting, sorry but I had to borrow these pics from other articles which were written by Mengu (First example) and Honza (Second example). I had gotten over-zealous with all my old pictures and re-adjusted and saved them before I could get before and after pics.

Before 1

After 1

Before 2

After 2

Hope this helps out!