Consider what you are going to wear. I typically recommend you pick out the clothing for the hardest person to dress and then draw colors from that person for clothing. Try to coordinate and not have everyone matchy match.
Example Mom’s dress has all the colors of the other family members
Consider footwear you want your photos to be cute but you also need to take into account the location. It may be best to wear something practical to walk to location and then put on shoes once there.
Consider booking hair appointments for color and cuts a week or 2 before your session. When you feel like you look your best, it comes through in photos.