STEP 1: Choose your base of choice. A base is an unedited/unaltered 100x100 icon; usually. Before you begin working on the coloring you should analyze your base. If it's too dark or too bright. Whether the cool (blue and greens) colors are more dominant than the warm (red and yellows) colors. This is VERY important when it comes to Selective Coloring, especially this tutorial. This probably won't work too well on images with excessive red or images that are too blue. If it has too much red it's going to end up making your subjects skin look--like they've been out in the sun for WAY TOO LONG. Unless, you're into that then you can just ignore this bit of info. If there is too much blue--it's going to just diffuse the edges of the blue and make everything pixelated. TRUST ME. You don't want pixely icons.

This is my base. Usually what I do with dark bases I just use the "Auto Contrast" button. It adds depth to the bases which is a good thing when you're going to brightening things up but don't want to wash it out too much. To do this you can go to "Image" > "Adjustments" > "Auto Contrast"
You can also choose whether you want to sharpen your image--but I rarely do that. It'll make the pixels that more obvious in a really bright coloring.
STEP 2: Duplicate your base layer and set to SCREEN.
You should have something like this now:
Still not bright enough for me.
STEP 3: Duplicate your base layer again. Set it on the top. Set to SCREEN.

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See? Now it's bright enough. Maybe a little washed out so we're going to add some DEPTH some UMPH to those colors. Okay? Okay.
STEP 4: Create a new FILL LAYER using
#ac8334. Set this to soft light at 23% opacity. THAT opacity is what works for THIS image. You can up it or reduce it depending to your image and your preferences. What this color does is add depth to the yellow and orange like colors. It may not be obvious now but trust me, it makes a difference once you start tinkering in SC.

>
STEP 5: Create another FILL LAYER using
#5a8756. Set this to soft light as well at a 32% opacity.

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The green is good for adding a smooth like color to the skin and other beige colors.
STEP 6: Now, it's bright but blanched out, no? Let's add some all around depth without resorting to color burn (which can be sooo ugly sometimes if not done right lol) and without using adjustment layers like brightness/contrast. Let's make YET ANOTHER FILL LAYER. This time using
#527195. You could also use any other dark blue. =] But I liked this color at the time.

Set it to SOFT LIGHT at 53% opacity.

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As you can see, some of the red has gone but we still have more intense colors than we had when it was just the screen layers. Let's make those orange and red colors in the background more rich.
STEP 7: Create one last SOFT LIGHT fill layer with
#a24b6e. Set the opacity to 12%. We want red but not TOO much. The Selective Coloring will take care of the rest.

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STEP 8: Here weee go. Onwards to Selective Coloring. Go to Layer > New Adjustment Layer > Selective Coloring. Put the following stats/numbers in their proper window. NOTE: Again, remember to tinker around depending on your image. The most important tabs to keep an eye on are the REDS, BLUES and NEUTRAL. The REDS are, as the name states in charge of the red colors. To keep from getting burnt skin I suggest putting very small numbers in the Black option of the REDS tab as well as the Magenta tag. If there's too much orange and you want a softer pinkish color use negative numbers Yellow option. Want more orange? Use positive. =] Juuuust a tip HEY LET'S KEEP GOING.
REDS
-100
+25
+56
+10
YELLOWS
-100
-25
-100
+15
GREENS
+100
-100
+100
+100
CYANS
-100
+100
-100
+100
BLUES
+100
+100
-100
+100
MAGENTAS:
+100
+100
-100
+100
NEUTRALS
+10
+10
-10
+5

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Now, you can leave it as is, but I usually like to combine TWO selective coloring layers. One to give the overall coloring, as in if I want an orange theme coloring, a pink kind of soft coloring, etc. And the second layer is what I call the "enhancer" layer. It's just a tweak here in there to make the colors pop out more to my liking. So, if you like you may continue or you make skip straight to step
STEP 8: Create another SELECTIVE COLORING layer and put in the following numbers:
REDS:
+15
+10
+25
YELLOWS:
+100
-22
-20
+12
CYANS:
+100
-100
-100
+100
BLUES:
+100
+100
-100
+100
MAGENTAS:
+100
-25
-100
-25
NEUTRALS:
-5
-3
+6
+1

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Can you see the difference? The blues and reds are slightly more vibrant and there's a certain depth to the shadows that wasn't there before. It's always nice to have bright images but I also like to still keep a contrast in there.
STEP 9: Another layer that I add because--I am picky. But you don't have to. I STILL want more contrast so I create a BRIGHTNESS/CONTRAST layer.
Brightness: -5
Contrast: +35

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STEP 10: I am...still unsatisfied.

So I duplicate the BRIGHTNESS/CONTRAST layer but lower the opacity 25%.

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STEP 11: I always, asides from a BRIGHTNESS/CONTRAST layer add a HUE/SATURATION layer. So, please if you may, create a HUE/SATURATION LAYER:
MASTER:
0
+12
0

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STEP 12: Because I am reaaally bent on burning your retinas, duplicate that HUE/SATURATION layer. Opacity to 100%

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STEP 13: I always, well yes always hehe add an exclusion layer. I don't always use the same color but depending on the image. This time I chose a nice chocolate red color like
#733621. Set to EXCLUSION at 30% opacity.

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Now the bright colors are still there but there's a certain softness that doesn't make you want to rip your eyeballs out from the ZOMG YOU HAVE ABUSED THE SC ONCE MORE WOMAN!...moment. Thing. And voila! you're done.