Lower the bar
Even great artists and illustrators hesitate before starting a new artwork. Only children don’t. They just begin. They usually don’t even care about the result but just enjoy experimenting and playing around. They don't have such a high bar yet and just go for it.
You can do the same by lowering the bar. That sounds easier than it is, which is why I will help you with the "TROEPboek" method (this Dutch word literally translates to junk journal). Using a junk journal has given me space in my head, room for creativity, lowered my fear of a blank page and has returned the joy of playing to my life.