For myself, success is making a photograph that impresses yourself!
What’s your definition of success in photography?
To me success in photography is the ability to carry your camera anywhere you go and constantly thinking about photography and making pictures that they will live forever. Yes I find it exhausting but it keeps me going and making better pictures by practising frequently.
For a commercial photographer, I think there is really only one metric for success: make your client happy.
For an artist, it’s about self-expression and making yourself happy.
For commoditized art photography, then its either highly skilled technics, creative methodology or an authentic story.