Make sure you read the signs if you're going to the beach and want to park your car. Most parking spots require a permit. If you do have a permit from the Hotel you are staying at -make sure you read it because most permits only allow you to park your car at one beach, not all of them. Most beaches are private so make sure you are allowed there. The ticket for no permit is not cheap and the Police goes around checking constantly. It’s always fun to take your bike to the beach –no permit necessary for that.
In the summer the Hamptons get totally overrun. It makes sense because summer is really the only time worth going. But just don't expect to be alone out there lol.