1. Discipline - in your form, in your diet, and during your workouts
2. A great work ethic - at a very competitive level, your whole life will be volleyball. There will be days that you don't want to go to practice or play in a match, but you have to anyways. You owe it to your team and yourself for all the work you put into the sport.
3. The ability to be a team player
Assuming you're already part of your school's volleyball program and you're on a club team, to get better at the skill side, I'd suggest practicing whenever you have the chance - going to clinics that clubs around you probably offer in your free time, hitting, passing, setting, or serving the ball against the wall to work on your form, or finding teammates to pepper with you.
I played volleyball for over a decade and finished my career as a D1 college volleyball player. It's a great sport that can open a lot of doors, but it's also an incredible commitment if you want to get serious with it. Best of luck to any current or future volleyball players out there!
Jessica recommends the following next steps:
To be a professional in any sport it will take a lot of time, practice, and perseverance! I would start by joining a local team with a strong coach that will teach you the fundamentals of volleyball. As you get more experience, you can then move onto a traveling team or play for your high school volleyball team.
You can be great at anything you set your mind to, just remember to never give up!
You must know that you can do anything you set your mind to do. Train hard in the weightroom and really focus on getting your form right as far as serving and bumping and timing your jump at the right time. Practice even when you don't feel like it. The best time to get better and to improve your game is in the off season so try to find a one on one trainer to help you and show you the right techniques. Good luck I know you can do it!