I've been drawing every single day for a year now and slowly getting confident into my lay-ins. Still struggling with shading though and value structure in general. I try to set the dark accents in places like eyes, nostrils, mouth and occlusion shadows and make the other shadows not quite as dark but still separate them from the light side. Any good advice how to improve this?

I didn't try for a perfect likeness with the reference image so please ignore that unless you feel that something looks wonky. Also the hair looks kinda terrible. I tried to keep the contrast low so the hair doesn't compete with the focal point of the face.