There are so many people taking so many photos, it can often seem impossible to take a unique and personal image. A guideline I enjoy: could my photo have been taken by another person on another day? The photographer Henri Cartier-Bresson described "the decisive moment" where the image reflects an absolutely special instant: it couldn't have been taken even a moment before or after.
Not every image holds up to these thresholds, but they're good reminders as we take our snapshots: what am I bringing to this image? Why this and why now? One of my personal practices is to go shoot iconic subjects, things we've seen shot by a million people all the time, and from there, see if I can see things in a new or at least relatively novel way.
As Susan Sontag so nicely points out in her landmark work "On Photography," there's a difference between a photo of a beautiful subject, and a beautiful photo. Working on this is part of the fun of photography.