Wear comfortable and supportive shoes, and make sure they fit your feet well. This is probably not your time to break in new shoes– stick to the tried and true.
Keep moving in different ways: your body is really meant to move, so your back, legs and feet can gets stiff and sore if you’re standing still for sustained periods. You can delay this with shifting your weight side to side, or bending your knees up, or coming up and down on your toes repeatedly. Just try to keep your body moving around consistently.
Consider compression hose/ socks: these socks can help encourage blood flow back up your legs toward your heart, and prevent pooling of fluid in your feet and ankles.
Stand on a cushioned mat or carpet if possible, as a softer surface can be helpful to delay soreness in your feet and legs.
Try to sit when you can: this ties in with point number two, to just change your position. When you’re taking a break or having lunch, try to sit– just putting your body in another position can be very helpful!