Skull sketching practise

Skull (front view), Strathmore 400 toned gray sketchbook, 9 in. x 12 in.

I’d like to do some portrait sketching and painting at some point but I’m not very confident currently. Hopefully, working through some exercises will help boost my confidence enough to allow me to try. Took my time with this sketch, working in graphite and white charcoal pencil.