We have to create a new layer, for an appropriate painting: Layer – New – Layer. The new layer should be placed lower than the contours' layer and paint it in a neutral color, selecting the Paint Bucket Tool.

Funny Winter Girl  Drawing

We have to color now the picture with the basic colors, selecting the Brush Tool of Hard Round type. To make the work easier, it's necessary to place each of the new colors on a new layer (under the contours' layer, of course).

Funny Winter Girl  Drawing

Usually I start painting
 
the eyes, so we have to create a special marking firstly that will have the eye's pupil shape. Paint it, applying the Gradient Tool.

Funny Winter Girl  Drawing

Erase the marking: Select – Deselect (ctrl+d) and select the Burn Tool to dark out that part of the eye situated near the contours:

Funny Winter Girl  Drawing

Insert the gleam after that, making use of the Gradient Tool with the same adjustments, of white color:

Funny Winter Girl  Drawing