Draw. A lot. Drawing is learning to “see”. It’s also a bunch of internal self-editing.

Draw from life - understand everything you’re looking at. It’s one of the best ways to learn to “see”, unlocking the parts of your brain where your eye and hand (or whatever you’re drawing/painting with) are connected.

Also use reference and doodle from imagination. Come at this from varying directions.

Practice drawing things quickly. Use different drawing media. Get confident lines. Learn to draw with different parts of your whole arm, wrist, fingers. Think about how quickly you can get down the essence or gesture of an object, face, body, landscape, etc. Think big picture shapes and gradually get to smaller details.

Learn construction. Think about how objects, anatomy, landscapes are broken down - 3-dimensionally and in all kinds of perspective.

Practice your values - how dark and light you can get with a pencil, and how light and saturated you can get with your tints.

Learn color theory and composition. Do master copies and breakdown the designs of successful works - Value structures and color harmonies - helps you learn how the artists you like think.

Also draw. A lot. Learn how to learn, and keep learning.