How Can I Become More Invested to Earn More Playing Time?

Ask your coaches and yourself this question, "How can I become more invested to earn more playing time?" Restate it as, "What do I have to become to earn more trust?" I don't know enough about volleyball to answer fully but there is overlap among sports. 

Here's an article about new Celtic Anfernee Simons and what they've asked him to do (play more and better defense).

Excerpts that might apply to you:

• I think the next part is coming here, understanding the standards that we have here and the expectations.
• Simons even indicated that he may not play as much as he would like if he doesn’t progress on that end, and partially blamed his struggles in Portland on effort.
• “Joe always talks about like playing fast, thinking fast and we require that at a really high level,” McMains said. “Being able to move from one coverage to the next, it’s a very high standard.”
• He saw the biggest difference in his awareness now that the team is practicing and scrimmaging together.
• Under Mazzulla, they’ve stressed thinking, communicating things they see on that end and adjusting on the fly.
• So that’s first is just learn the system and then number two is now actually develop your ability to do those things at a high level. So it’s learning the system and then it’s also, can he improve his ability to guard on the ball with different different techniques?

For example, a front row player must:

• Defend the position, especially blocking. That means being in the right position by reading, reacting, and executing against the opponent's top attacker. If you play middle you have to be able to close the double block.
• Attack with the "Total Football" analogy - conditioning, versatility, awareness, and belief. Awareness allows you to smash, tip, or sometimes hit roll shots
• Specialty attacks rotating outside or with slide attacks
• It also means getting in position to attack 

"Your paycheck (playing time) is your responsibility." Be relentless. Run to the block, use proper footwork to close blocks and to get into attack position. 

Because you want to play more, fulfill the responsibilities, both physical and mental of the position.