I believe someone is in a state of wellbeing when they are growing as a person, contributing a net positive to the world, and caring for their physical, emotional, and spiritual health.
My model of wellbeing would be based on these attributes:
Emotional State: feeling well emotionally.
Physical State: engaging in actions that are physically healthy, and mitigating actions that are physically unhealthy.
Contribution To The World: contributing something to the world. This could be in any medium (art, emotional support, economic support, inspiration, etc.) But the contribution must be net positive to the world, meaning that the person is not taking more from the world than they are giving back.
Spiritual State: feeling well spiritually.
Growth: the person is growing in some way everyday. This could be intellectual growth, spiritual growth, emotional growth, etc.