Every new thing you learn to draw will share similar struggles, like learning a new piece of music. It takes a patience and a regular practice. I think all artists go through it.

My advice is to be working weekly on your fundamentals, shapes, forms, figure drawing, environments etc.
Then you will know how to apply those skills to learning any new drawing.

Draw from life: The books Keys to Drawing, and Drawing on the Right Side of the Brain are good for sharpening your general drawing skills.

Choose a new character you are interested in learning. Collect reference images, and then applying what you learned from your fundamentals training, you will be able to learn to draw new things.

It takes time and commitment like all other skills. Put in the hard work, and you will find your drawing abilities rewarding you with anything you can imagine. Keep growing :)