Polo and or collared shirt, no t-shirt. Paints, slacks or trousers, not jeans, nice or expensive for not. You can get nice reasonable slacks 2-4 pair. No tennis shoes. Boots, boat shoes, or other leather shoes. You are a professional pilot now. Dress and act like one.
appropriate female attire if that is the case. We have one in our class former 121 pilot.
PM me for any other specifics.