You want to have a good level of fitness. You start out with cardiovascular fitness so that you have the endurance to handle long rallies.
Also, you want to do weight training, and we prefer Olympic weightlifting. You can do that at the gym. Every part of the body is important for weightlifting.
You want to work on your core, you want to work on your leg strength, your back and your arms. And also for jumping, plyometrics, that's single leg hops, hops onto boxes, and other things like that.
You're never too young or too old to play volleyball, especially beach volleyball. I have friends who are in their 60s that are still excellent players. It's easy on the joints, being that it's a sand sport. And those are the basics, if you want to train for beach volleyball.