Dress for the heat, but bring a jacket or extra cover-up to be used while you are waiting to go on. Bring a handkerchief or tissues to dab perspiration during breaks. Don't second guess the camera. Act as if you are always on screen. Make sure your makeup, wardrobe, and hair are consistent with your message.
Men Wear knee-length socks.
Single breasted jackets can be opened, but not too wide. TV lights can penetrate several layers of skin. You can't possibly shave close enough to prevent whiskers from showing without makeup. Don't forget makeup on receding hairlines or bald heads. Run the thin part of your tie through the loop in the back of the main part of your tie then clip the thin part to your shirt below the loop.