https://www.skillshare.com/en/classes/Creating-Quick-Digital-Illustrations-on-Photoshop-Even-Without-a-Graphics-Tablet/442264411

This class will help you develop a good understanding of some techniques that will speed up your illustration process using Photoshop. The skills taught in this class is especially suited for aspiring comic artists or people who are looking for simple techniques to quickly create illustrations even without a graphics tablet.

This class is for beginners with a little bit of knowledge of Photoshop or any other digital art software but intermediate level artists might find some of the tips useful as well.