I use levels, curves, and some other things. I'd be glad to answer any questions on it with anyone. I used selective color, or just the basic hue/saturation and use the drop down in it for individual color choice and adjust them if necessary. I use two layer alot never more than two at a time. The reason for two is because i use a layer mask  to erase thru places i want to erase if i have a certain effect on the upper layer.

I may increase contrast in selective areas even, or even use more saturation in selective areas only.