I have a little Moleskine (3.5 x 5.5) notebook that I only draw skulls in. I started in November of 2013 and I do one whenever the urge strikes me. It's not like a skull-a-day thing but sometimes I do get into a period where I will draw one every day for a while then I won't draw any for months. I even lost it for a while and was very sad. I think the longest gap between pages has been a year. This is the most recent skull, drawn on 05.28.2018. Most of them are posted on my Instagram but you have to scroll back a ways to get at the bulk of them.
So I worked on this, using an older pic I drew from a few years ago, and am honestly happy with the results. this has got to be one of my most favorite DIGITAL drawings I've done. God be with you and guide you on your own drawings with your own talents.