Have your costumes organised in order of your dances in your garment bag, including shoes. 

Layer your stockings - e.g., wear tan stockings under pink stockings if your ballet dance is first and requires a quick change. 

Seniors - Pull down your ankle length tan stockings and tuck them into your shoes instead of changing into footed tan stockings.

Wear a skin-toned body stocking - this means you can change quickly without worrying about modesty.

Practice your quickest changes at home prior to the concert!