When I say the context, I mean the type of team you have and the priorities you have for them. Warm-ups for a group of 12-and-unders will be considerably different than for elite college level athletes, for example. The kids won’t need all that much to get them physically ready to go, but the college players may. Similarly, warm-ups for a team whose focus is primarily on development might be quite different from those in a mainly competitive environment. A developmental team can use warm-ups to help skill development while for the competitive team may want to simply have the most efficient way to prepare players’ bodies for the rigors of gameplay and perhaps work on tactical elements.
As for purpose, what I mean here is what your warm-up is intended to accomplish. Is it to get players ready for training or for competition. Is it mainly physical or mental, or both? Using the example above, while a physical warm-up for 12-and-unders probably isn’t really necessary, a mental one could be quite important to get them focused at the start of a session. Likewise, getting ready for a match could be quite different from getting ready for practice.
Make sure you have a good handle on both context and purpose as you plan your team’s warm-up. As for the sorts of drills you can use, here are some ideas.
A dynamic warm-up will probably be a good starting point. Basically, a dynamic warm-up is one which gets the body ready for action through various type of movement. You can find examples by searching YouTube. The old jog & stretch routine is increasingly being shown to be ineffective, if not down right detrimental to performance because of the impact of static stretching on the muscles. You’ll want to avoid that.
The dynamic warm-up is quite good as a general physical warm-up and doesn’t take all that much time. If you have specialized needs, you’ll want to address them, of course.
What follows the dynamic warm-up – or perhaps even replaces it, depending on your circumstance – depends on what you want to accomplish. If you want to incorporate skill development in the warm-up, you could do something like ball-handling drills that keep the players moving and active, but also works on their fundamentals. If you have more tactical needs, you can put the players through low-intensity versions of game-like drills by taking out the jumping and/or hitting elements. In the case of a pre-match routine, you’ll want something that is consistent and not only physically prepares the players for play, but also puts them in a good mindset (think high success rate drills).
There are numerous ways you can construct a good volleyball warm-up, probably with drills you already know. You just need to think about the requirements of your warm-up and make adjustments as required. Make sure the warm-up is right for your team and situation. Don’t get caught up in doing what anyone else does.