Our photographer said to keep something similar on each and don't wear anything with numbers or letters on it. We had all of our boys in different shades and styles of denim shorts and some with white singlets (these looked great in black and white and she had them all sit on a fluffy white rug), some with different colored singlets (red, black, blue, etc) and some with no shirt. All had no shoes too. I have seen some great ones with the kids dressed in costumes for something cute? Good luck - family photos are so stressful!