There are tons of great tutorials online. I tend to like the readable ones over the videos because they are easier for me to follor.
Layers are great, always use layers. I like curves a lot.
My favorite thing to do is push all the colors. Go to red and do
Red: 150
Blue: -25
Green: -25
go into blue and do
Blue: 150
red: -25
green: -25
and go into green and do
green: 150
red: -25
blue: -25
if there is a person in the picture, erase the layer from their face. Here is an exaple of a picture with colors pushed