ICON COLORING TUTORIAL, CUT TWO BLACK HAIR woah scandalous
EDIT: OMG I DON'T KNOW IF THE CANC BUTTON IS CANC IN AMERICAN KEYBOARDS. Pretend it says "Del" or whatever you use in its place I'M SORRY I FORGOT
ALL RIGHT first of all I apologize because my english is not spectacular, and I'm not much of a good teacher. But if anyone has any questions and need specific help, drop a comment and I'll see what to do. Now, first off, we start with our image! Since I was asked about my Morgiana set specifically, I just picked another Morgiana image and went with it.

This image happens to be pretty clean already so no need to do anything but take off the writing on the left! Now onto the coloring, first thing to mention is that for icons I always color above the lineart. Make yourself a new layer, above the picture you just opened, and put it on linear burn.

The first thing we'll color is the skin. The color I picked for it is #ffdec8! Now, this is an important step -- a lot of people just color with the brush tool or whatever, but that makes it a little hard for people with no tablet/can be very frustrating if you're not precise. How to bypass that? Well, I use the tool Polygonal Lazo. You'll find it on your tool bar right under the square selection tool. Here it is, and the settings at which I keep it.

Now zoom in, and using the polygonal lazo make a selection around the skin. Don't worry about selecting things that you shouldn't -- we'll delete them later. Now look, a selection!!

Press SHIFT+F5 to get the fill option, put it on foreground color, and press enter. This will instantly fill the selction (make sure your linear burn layer is the one you have selected).

As you can see, that filled the eyes as well, so once more let's go and select AROUND THE EYES and then press canc, to take the color away.

Next thing we'll color is her outfit. The color for this is #ecd7ae! Like before, let's make a selection around her outfit and then press SHIFT+F5 to fill it in. Note, this is still on the linear burn layer. Do not make a new layer! Here's the result:

Now let's take care of the eyes and her hairtie. For the eyes, the color I picked is #de3b3b, while for the hairtie it's #fad658. The process is the same as before, so just select and then fill in.

Wow how awesome we're like totally almost done. Sort of! What to do now is duplicate your linear burn layer. Simply right click on it and go to "duplicate", and once you've done that, put your new layer on Soft Light. Make sure this layer is ABOVE your linearburn layer!

And now we go to the tricky part. Make a new layer and put it on Hard Light -- this is the layer we'll use for the hair. Before we go, a little note -- this may not work for black hair all the time. This method works well with Morgiana due to her hair color + the way Magi puts highlight on the hair -- wile it's generally a good trick, you might have to work quite a bit to find a color that will work well. Either way, trial and error is always the best method, so my suggestion (and what I do) is to keep trying all the colors until one that looks satisfactory comes up.
For Morgiana, the hair color I used is #b90000. NOW, another important thing! Like before we're gonna do a selection around the hair however, make sure to leave a small black line to keep a "border" and give the impression the color was like that since the start, rather than colored black. I'M SORRY I CAN'T EXPLAIN WELL, so I hope the image will show what I mean.

Like before, press SHIFT+F5 to fill in the selection we just did. Don't take the selection just yet, and instead go select your soft light layer, press canc, then do the same for your linear burn layer. This will take care of any color that you put on the hair selection before. Now let's make a new layer, and put it on multiply, with opacity at 70%! We need the hair selection again, so, if you if you took it off just hold ctrl and then click on this little square

Anyway, so far this is what you should have

What we will be doing now is use the gradient tool. On your toolbar right click on the bucket and then select the gradient tool.

We have to change the settings a bit! First off, we need to pick the gradient option that goes foreground to transparent.

After that, let's put it on mode "multiply".

We're ready to abuse our gradient! With the hair selection still on, and making sure you're clicked on the multiply layer you did before, using the gradient tool make a line from bottom to top. Repeat the process a few times, enough so that the difference is something you're satisfied with. It really depends on you so just go with what looks best to you.
Here's my progress:

Now, to me it still looks a little flat, so we're going to add lighting as well. Make a new layer at Linear Dodge (Add), and with the hair selected, make one line with the gradient tool just like before -- only this time we're going top to bottom. I usually do two at max, but again, this depends on your own taste. This is our result!

Time for the background now. For Mor I picked #ffc557, because it's a color that gives enough contrast to her, but again, this is all up to your personal taste. Go make a new layer on multiply, above the lineart but under every other layer, and fill it in.

Now use the trick I explained before to select everything in an image, press ctrl+click on the layer square on our linearburn layer, and then go to our background layer and press CANC with the selection still on.

Resist the urge to cry and screa at the terrifying sight and now select around the parts that should be white, and just delete them.

We're saved from the freaky eyes and we've got the panel done, hooray!! Now, to turn this into an icon, go to layer, flatten image, and put it all in a single layer. Now go to Image > Resize, and put it at width 120. Go to Select > All, and then Edit > Copy.
Make a new image at 100x100 pixel and then go to Edit > Paste -- and move the image around until you find a crop you're satisfied with.

The colors are a little washed out, though, so what I do is usually play around with filters and stuff. For Morgiana, here are the amount of filters I use:

... And here is the final result:

I can't share the PSD of the touchups (since this set was commissioned), but trust me when I say the way to do is play around with things until you find something you like. You can find a psd of the first steps (ie no touchups, just coloring) here, so hopefully that will help where I failed to explain. As I said, for any questions don't hesitate to ask! A small note -- in here I put the border on the hair a little too thin, so upon resizing you don't see it well and the effect is not very good, but I was too lazy to redo it from the start. Try to keep in mind that you will resize your panel, so don't make your line too thin!
Last, a reminder that I take icon coloring commissions here.
THANK YOU AND I HOPE THIS HELPS!! ♥