First, before taking a photograph, ask yourself honestly what you like about the scene/subject and then focus your efforts in that area. 

Second, my own theory is that an interesting image consists of three primary elements in varying degrees: (SLC)

            -  SUBJECT

            -  LIGHT

            -  COMPOSITION

Any one of the elements can dominate the others and still produce an interesting image.  But the absence of any one of the three elements, will result in a less than interesting image.  The hard part is complying with the rule.

Third, start taking pictures.  Below are a few things to do before and during a shoot.

       -  Check / Reset all camera controls before shooting.  (e.g. expose mode & comp)

       -  Start with  "Snapshot"  of scene.

       -  Move in, optically, & isolate elements of scene.

       -  Bracket 1/2 stop over/under, ... re-focus ... re-shoot.

       -  Enhance image, if appropriate, with filter, etc.