Your personal experience is a factor, e.g., onsite knowledge is a great aid in image interpretation. If you are going to interpret images you should devise a checklist for the following elements to aid in identification of features. Irregular vs. geometric may be a clue but not always, e.g., fault lines may be straight. When analyzing photos or images look at the shape and think about what it may represent. Smooth surfaces tend to have high reflectance, rougher surfaces less reflectance.
High reflectance tends to create images with light patterns, for example, sand, bare rock, or roads.
Vegetation varies from light to dark depending on species. Vegetation is much more reflective in IR band and may appear lighter. Areas blocked from radar signal appear dark. Closest to our perceived notion on natural color images but may appear washed-out. Time of day has a great deal of influence as do shadows.