automejorarse

A less common alternative to the far more usual mejorar, emphasizing that the improvement is self-driven — used mostly in self-help and personal-development writing.

• Se apuntó al curso para automejorarse profesionalmente. — He signed up for the course to improve himself professionally.
• La app ayuda a quienes buscan automejorarse cada día. — The app helps those looking to improve themselves every day.
• Automejorarse requiere disciplina y paciencia. — Improving yourself takes discipline and patience.

Sounds noticeably more formal and jargon-heavy than everyday speech — in ordinary conversation, superarse or simply mejorar is what a native speaker would actually say.