Knowing where to go when you want to become a self-taught artist isn’t easy. Some people choose to base all their knowledge on one artist or one course. I recommend though to look up several artists. Learn to see things in different perspectives, and see what fits you best at that time.
Creating a creature from scratch sounds wonderful. You wake up from a dream and have this wonderful impression of a great beast. But when you are drawing from imagination, it’s nothing like that mighty beast you saw in your dreams. Why is that?
It has little to do with your skills in art, the explanation is more complex and interesting than that.