I think most people would agree that critiques are one of the most helpful learning tools to become better at photography. Some critiques are really helpful and can even give you a -lightbulb turning on- type of moment. Other critiques may make you feel good (like "great pic!") but that type of critique is useless as it doesn't help you improve. In my mind I try to go through a systematic approach to evaluating a photograph.
1. technical aspect: exposure, subject, lighting, focus, white balance, etc
2. artistic: composition, lines, texture, overall look and feel, mood, emotion, etc.
3. post processing
I try to note both the positives and the things that could have been done better.
5DII. 50L. 24-70LII. 16-35LII. 70-200is2.8II. 100L 135L.