Your sketchbook is a space for experimentation. It's a space for you to try out different mediums and styles until you decide what clicks. It's a way to test out ideas before you make your mark on a canvas or high-quality art paper. Sketchbooks are supposed to be messy. Now this is a mindset that took me two and a half years to grow into. I've come to realize that the better you become at art, the easier it is to give yourself permission to get down and dirty.