Sorry for the late reply I just painted very carefully with water color after an initial sketch with blue lead XD Normally for this kind of thing people use miskit or some kind of masking fluid; however, I don't haha (; I just use a really tiny brush to paint around the outline.
I'm not the artist of this, but I've done paintings recently with the technique I'm sure he/she used. It looks about 80-90% was done with masking fluid and the rest little add-ins after it was dried. Here's an easy tutorial to follow. [link]
Thank you I just sketch out the wolf, and then paint with watercolors. It's a lot about working with negative space. Instead of coloring the space that is occupied, I focus on painting the space that isn't occupied or space that is in heavy shadows.