So many people want to know how to prepare. The easiest way to figure out things is to really think about your session. Start by thinking if you want a theme, if your modeling, or are having a family session, ect. Some people enjoy going all out with themes.. Some just want some standard photos and really don't think much on anything but keeping it simple. So the big question to ask yourself is... "What do I want to represent myself or my family and I?"
So once you have figured out what type of session you want this will come natural. Depending on your location, the weather, and of course a possible theme your wanting is how you would figure out what to wear. Here's a few examples.
Lets say you are doing a family session and you want some nice casual photos, your not really wanting a theme, but you want the photos to be the best for a forest and beach kind of area. So thinking about colors. Now trees are brown and there are lots of greens and yellows depending on the time of the year this could be different. You have sand that's white, ocean that's blue and the sky which is also blue and white (if there is cloud coverage the day of). With all of these colors I personally think in the forest that ivory, cream colors, pinks or blues look really great. You can wear clothes that fit your skin tone well and pop your eyes out. Blue eyes wear some blue, green eyes wear some green (but in a forest you want more of a dark green or even a pattern that just has a tint of green not to much to blend), and brown eyes really pop with pinks and reds. I recommend you have a color theme but blending in to much will not be good so when getting clothes together be sure your not all wearing the same colors. If you look at the image to the left blue was the color scheme and they matched very well together.
Another option for style in a forest area with lots of yellows and greens is light pastels, or deep colors. You always want to blend well with colors that are not of your backdrop. Really think about your location. Wear Ivory because white reflects so many colors that in photos its not always the best. I prefer more solid colors but if you want to wear a pattern make sure its not overwhelming in the pattern. As you see to the right the mother has a cover to give a solid balance and her daughter is wearing ivory with a tint of pink. Matching color are great and often better than trying to wear all matching clothing, shoes, and accessories. Even with twins in photos they have slight changes with colors so its not blending together to much.
The best website I have come across to what to wear tips is located on a really nice website/blog called Paint the Moon. If the examples I have given you are not satisfactory please check out the site because it explains everything in great detail. Click Here