How can I maintain my body and energy in a more physically demanding job (details)?

I picked up a second job for the holidays temporarily: Retail. This is my first time doing it (my first day was black Friday, in women’s shoes…...) and it’s pretty challenging physically since I’m not used to running back and forth fetching shoes for 8 hours.

It’s exciting (for now), but I now know I need more comfortable dress shoes. What else can I do to make this easier on my legs and body?