Any true artist or creative already knows the answer to this, the photographer I want to be better than is me!
After every shoot, commercial or personal, I study the images I've produced. Did I get it right? Could I have posed the model better, chosen another angle of view, used the lighting in a more interpretive way, created a stronger sense of mood, etc? The answer is, 'Almost certainly!'
Honest evaluation is probably the most powerful tool any artist has at their disposal, being truly self-critical takes years of practice. Listening to feedback from viewers, and assessing it, is a very valuable skill. It can certainly dent your ego when the criticism is valid, but it might just set you on the way to not wasting your time doing the wrong thing. Eventually you will reach the stage where you just know when something you've produced is good.
Of course, like any other visual artist, I see staggering work by others, and think, 'Why don't my images look like that?' The answer is very simple; I didn't take them! The style, intent and skills used were different to mine. I can still draw inspiration from them, and continue on my own path, interpreting similar ideas and adapting them to meet my vision.
And so, to the many great photographers whose work has intrigued, illuminated and inspired my journey, I say thank you for making me want to be the very best image-maker I can be. The only true respect I can show you is to keep improving!x