Hello:

I am from Mexico. I am living near to the beach, in a port called Acapulco. Have you been there?
The most interesting activities that you can do there are: go to "La Quebrada", it's a place where you can see high nails into a cliff, it's very dangerous but pretty amazing; also you can go to restaurants and bars at night, the the mood is very fun and relaxed; you can camp on the beach, to see the sunset and also to receive the sunrise.
I recommend you to come in non-holiday periods, so the prices of hotels are cheaper and there is not many many people as vacations.

Thank you for reading!