The first thing to know is that there is no right or wrong answer. Every photographer will have different preferences. Truth be told, the photograph is ultimately about you and/or your family, so do what feels best.
Do Wear:
-What you like to wear and what you feel good in, that’s the most important.
-Coordinating outfits are great.
-Accents and colors that compliment each other are the goal. If the baby is wearing a particular colored shirt, maybe Dad’s collared undershirt can accent that color. If Mom’s wearing a certain color, maybe she can accent the color theme with her accessories.
-Colors that you know work well on you.
-The feeling you want to convey; lighter shirts on top give the pictures a more casual and bright look. Darker shirts on top give the portraits a more serious and thoughtful feel.
Don’t Wear:
-Big logos
-Busy patterns that may overwhelm the photo, and distract attention from the subjects and your expressions
-Things that are too reflective, some eye make-ups that have glitter in them, and things that shimmer will also reflect the camera flash. They can be distracting and can look a little weird.
-Try not to wear the same exact outfit as the other
Hope that helps!