This helped me a lot...

[firstservethenvolley]

Okay, there is this friend of mine who wants to play tennis. She had previously played for like a couple of months and can return the ball over the net. I went out to the courts with her and said I'd feed the ball to her. I was standing at the net and returning the ball back to her while she was hitting it on either side of me. I think this helps you volley as you have to get the ball back where she is and you should also stop her from passing you. What do you guys think ?

p.s. After this I went out and hit with a wall(a solid 7.0) for my groundies.

 

[Duzza]

Yeah. Once I hit with this guy by feeding the ball to him and then returning it back to where he was standing. It felt like I was improving my groundstrokes. What do you think?

I would say volleying back to a beginner who is hitting the ball at 30 mph won't exactly be tough now will it? Try standing in the service box volleying back 100mph serves, that is good for your net game and reactions.