Coordinate and Complement
When styling your photo session, I suggest choosing a basic color palette and then going from there. It helps to have one "rock star" who wears the pattern and then coordinate others' outfits and accessories around that person. For whatever reason, I find that it's sometimes easier to find patterns in women's and girl's clothing, and then accessorize the men/dad/boys around the ladies.
Scarves, hats, flowers in the hair for little girls, statement jewelry, vests, and sweaters...these accessories can take an "okay" image and make it feel complete. However...don't allow the accessories to overwhelm the subject. Accessories and clothing should complement and not compete with the subject.
Layers and Textures
...create interest in photos. They add interest especially when used with neutral color palettes. Texture can be achieved through the use of different materials, including: tweed, crochet, lace, and tulle. Layers and texture add dimension and depth to your images!
Consider props that blend with the overall "feel" of the session. Flowers that coordinate with a pop of color in the subject's clothing, a vintage camera, a child's favorite stuffed animal...The prop should make sense and not become a distraction. The best props are those that are meaningful to you!
Keep A Timeless Look
While this is more of a personal preference, keeping a timeless look can extend the life of your photos. Make sure that your clothing choices won't look terribly dated years from now. One way to achieve this look is to choose vintage or classic styles. Again this is only a personal preference. Some folks prefer to be more trendy, allowing their photos to serve as a time-stamp of in their images which is totally okay also!
Make sure that your clothing choices are comfortable. This will prevent the need to pull at your clothing throughout the session. Believe it or not, when you are uncomfortable, it shows in your images. Make sure that you select an outfit that makes you feel stunning and relaxed. *Helpful Hint: Ladies: If you plan on wearing heels for your session, also bring a pair of flats to change into. This will ensure that you will be comfortable.
Think About Your Location
...and make sure that your clothing selections complement the surroundings. Flowy dresses and vintage pieces look amazing in a field, farm, or rustic setting. Those same pieces however, might look out of place in an urban setting. Often, I begin with choosing the location, and then decide on outfits and accessories that will enhance the overall vision of the session.