if I were you I'd practice masking. once you get a quick mask on something make it a selection and go to curves and boom you can change the color of it, a lot of thing revolve around a good mask
also learn shortcuts= b = brush g = paint fill m= marquee tool etc etc etc
here's a crappy demo of a quick mask and color change on curves
(the mask it crappy because i used the mouse, kinda like drawing with a rock lol)
before
After
it's a place to start