A handy little tool to have at your disposal is knowing how to critique a photograph, either your own or somebody else’s. Being able to look constructively at your own photographs will allow you to improve and grow as a photographer, and you can use the exact same process to "pick apart" images from a photographer that you admire, so you can see what elements appeal to you, and try to purposefully add them into your own images.
Mostly you will tend to like or dislike a photo intuitively and whilst that is a great basis to start from, it's helpful to go a bit deeper sometimes and dissect some of the photos that you like, and even the ones you don't. Although art is subjective (what one person likes another person does not) you should still be able to break down the image into the various components and critique them - things like focus, exposure, white balance, compositional tools and so on.
Go grab an image - either one of your own or somebody else's - and ask yourself the following questions when looking at the image.
Is the subject properly exposed?
Is there any clipping (blown highlights) in any important areas?
Is the subject in focus, or are there any areas "soft" that should be sharp?
Has the appropriate depth of field been used?
Does the depth of field used add to the image?
Is the white balance correct?
Is the subject lit in a flattering way?
Have the light been used in an interesting way?
Are there shadows to help give the image depth and dimension?
Are there catchlights in the subject's eyes?
Is the light highlighting any details that detract from the subject?
What was your eye first drawn to in the image?
Did the photo clearly show what the main subject was?
Does the chosen point of view enhance the composition?
Are there items in the shot that doesn’t add to the image?
Or something in the frame that helps add to the image?
Are there any unflattering chops?
Which compositional tools have been used?
Does the subject look connected and comfortable?
Would further editing have added anything to the photograph?
Could the image have been edited differently to provoke a different feeling or message (for example, softening, more color, added a vintage feel or processed in black and white)
Has post processing been used to cover up any flaws?
Are there any obvious areas of cloning?
Message / Intent
Does the image provoke or show an emotion?
Does the picture demand your attention?
How did the photo make you feel?
Did it inspire you and if so, how?
Did the photograph convey energy, intensity or any other emotional impact?