Volleyball is a game to play with friends, same gender or coed - even reverse coed. It does not matter if those you train with are only 7-years old, or your grandmother. As long as they can provide you with the unique angles of the game, you'll be learning fine. The other essential key for learning the right habits for game play is a net. Even if it is a rope, or an imaginary net above a line on the ground, you will ALWAYS be LAYING with a net, to hit over, set along, pass from a served ball over, etc. The more you use a net, the better you'll get, so create one!
WHAT IF YOU HAVE NO FRIENDS OR NET?
When this situation occurs, you need not take up solitaire, but you need to watch out that you do not teach yourself ―bad‖, non-game like habits or reactions. Sure you can bump the ball to yourself but would you ever do that in a game? Not a likely desired action, as you most often send the ball to a teammate or an opponent. So what can you do?
Serve against the wall
Mark a line at the height you play and stand back 9 meters or more and go through your routine, serving over the line. It is most important that you have the skill of always serving over the net, even if you sometimes serve out. Go through your whole routine, and imagine each time that you are in a pressure situation and visualize your successful, tough serve. Remember to serve, even against a wall, from all areas of the end line, not just the traditional zone one/right back area.
Serve and dash
Most people forget that the whole skill of serving really includes dashing to their back line defensive area. For those defending left back, and choosing to serve from right back, that is a good 8 meter or more sprint. As you run you should be watching the ball - run and watch, not watch then run - to determine what small adjustment you should make on the next contact to better float, or topspin powerfully, the serve.