In preparation, I drew the outlines of the drawing with the pencil tool.
Now, create a new layer and place it under the line drawing.
From the [Selection] tool palette,
I choose [Refer only to editing layer] and use the [Fill] function on the [Selection launcher] to color the whole area.
Then I create the base for the skin color.
I'm going to use the [Oil paint] brush.
This [brush] can be found in the [Oil paint] sub tool palette.
I choose a color from the color wheel.
I select the color for the shadow from the [Color] palette.
Using this I will draw the shadows next.
The brush size can be changed in the [Tool property] palette.
At first, I paint the parts that will be in shadow and the parts that will be brighter very roughly with a large brush.
It's easiest to zoom in using the [Navigator] palette for this.
Next, I select another brighter color and apply it to parts that need to be brightened.
Usually I continue like this until I'm satisfied with how it looks.
By the way, if you have a particular color you want to use again during the process,
it's useful to refer to the [Color History] palette.
Now, if you want to choose a color that's close to what you have but maybe a bit lighter,
you can have a look at the [Approximate color] palette and choose from there.
Also, if you want to draw small details,
it's a good idea to create a new layer and draw those on there.
I create a new layer, change the blending mode to "Color burn" and add a gradient shadow to the character.
Finally, I'm adding a simple gradient background.