My T-shirts go tucked in; your mileage may vary. I do find that in summer, the shirt helps wick moisture out so that my waistband is drier and cleaner. If possible, leave off the belt & you'll stay cooler.

If you wear boots, socks may be up, scroonched down, or regular crew socks. You can wear sandals, if you prefer! although in a crowd that may be dangerous to the toes.