Have a snack or sweet available for parents to munch on. Cheap pretzels and chocolate are my go-to.
Greet parents at the door. This helps them feel welcome and know that they are in the right place. Standing at the door also keeps me from awkwardly standing at the front of the room while parents arrive.
Say goodbye at the door. This helps to avoid any parents who might keep me from getting home before I need to wake up again for school the next day.