When you first arrive, you realize how popular these beaches are and how packed they can become. Luckily for us, the day was overcast and there were some scattered showers that really helped to cut down on the number of people.
The trick is that once you reach the sand, head left (southwest?), and there is a path into the woods that looks pretty dubious. Have faith and keep going. Once you emerge, you will be at a secluded beach away from the crowded public beach. It is substantially sized, pristine, and amazing. Just don't forget to bring your refreshments, since you won't be finding vendors or bars anywhere nearby.
Our group had a fantastic time swimming in the ocean, and the waves were easily big enough to knock you over. We spent our time in equal shares of swimming and lounging in the sand. There was even a roped-off sea turtle nest! That part made me really happy knowing that I was that close to such beautiful creatures and that Puerto Rico was doing its part to protect them.
It was the most amazing beach that I have been on and will certainly be something that I remember forever.