It is the quest to be better in each and every facet of life. The process of becoming a better or more informed person can be called self-improvement. Sitting up every night and learning to speak Mandarin could be part of your new self-improvement routine. Self-improvement in and of itself involves making changes to your total life strategy.
These are the sum total of all the behaviors, thoughts, beliefs and responses (both conscious and unconscious) that you use to meet your needs, achieve your goals and overcome life's problems. The ultimate goal of self-improvement can be paradoxically counterproductive. This is what healthy self-improvement looks like.