What accessories or undergarments are required when a girl wears a dress?

Dress

Well, it depends on the type of dress and the time of year. If it is a formal dress you probably want to wear sandals with some kind of heel and carry a small purse. Also, if it is cold you should probably consider pantyhose. For more casual dresses you can wear heels, but also flat sandals and possibly boots will work depending on the dresses style.

And the list goes on:

Undergarments can include:

• Bloomers, slip, or shaper-pants
• Body shapers for adults
• Spanx
• Bra
• Panties
• Garter belt
• Corset
• Pantyhose or tights (for more formal or business dress)
• Camisole
  diaper and/or plastic pants
  
  Accessories can include:
  
  
• Jewelry (earrings, necklace, bracelet, finger rings, watch, or decorative hair pieces)
• Purse or handbag
• Hand muff
• Belt
• Shoes
• Toe-ring (if you dare)
• Acrylic nails
• Shawl, wrap, bolero, shrug, whatever you want to call it
• Gloves (do not wear jewelery over gloves, not proper etiquette)
• Fan
• Hat
• 
  in some catholic churches when girls wear white dresses for baptism,first communion and confirmation they are required to wear a diaper,plastic pants and tights and under shirt.i had to this for my confirmation at 16.