Subjects with repetitive patterns can make for interesting images. For instance, cropping in tight on a decorative door can abstract the view and lead the eye. Also look for deviations in patterns – what if the door feature had a an interesting handle? Now you've got a break in the pattern that creates a strong point of focus.
Patterns are all around us, both in nature and in man-made structures. Using patterns in your images creates a sense of rhythm and harmony. Patterns appear when elements such as lines, shapes, colors, or forms repeat themselves. The secret to finding patterns is to look at your subject and image from different angles and viewpoints. The patterns seen in the colorful umbrellas lined up on a beach may not be as obvious when viewed from ground level, but are much more obvious when viewed from your hotel balcony. Move your feet, mix it up a little!