How to get my volleyball serves just right?

how can I practice my serving so thats its not so hard it goes out of bounds?

If your overhand serving which I amuse you are you are hitting the ball at to high of an angle causing it to go out. If you can serve it out thats perfect. strength wise because it's a hard ball. Try a float serve. Its pretty much the same technique but you hit the ball a little earlier and some people throw the ball higher to just to time it better. Good thing about a float serve is that it changes directions in the air slowly it hard to explain but there are the best serve you can use in a game