Method #2: Hue/Saturation Adjustment Layer on top, with the Saturation Slider all the way to the left (no color - it's now black and white). Now, below your Hue/Sat layer, make a Levels Adjustment Layer (or Curves - your choice - I just prefer Levels for broader strokes of change) and again, change individual colors.

As you change individual colors, you'll notice it's a bit muddy - you're changing the density of specific colors for whatever effect you're going for. This is why I usually make ANOTHER Levels Adjustment Layer below the first one and only adjust the main RGB setting - black, white, and middle gray. This will give it more punch.

And just like the previous example, I made a Soft Light Layer between the Adjustment Layers and the original image. Paint to dodge and burn to your heart's content.

As with everything in Photoshop, there are about 20 different ways to do anything - play and have fun! Figure out which methods you like because what matters is the final print.

Good luck, and I hope that helps-
-Lew ;-)