I taught my puppy to place the toy in my hand by using a larger toy than a ball, something we could both hold onto at once. How far along with 2 ball are you? Does she drop it on command? If she does then it's very easy. I used a frisbee, and when he brought it back to me I held it and gave the release word. After a few times, he was giving it freely. Then I introduced the word "hand" when he released it. He caught on very fast, but sometimes he'd just drop it at my feet. Then I'd say "hand" and wave my fingers and look at the frisbee, then back at him. Back and forth until he'd pick it up and give it to me. I didn't pick it up for him, he had to do it on his own. Good luck!
There are two commands:
1) "Drop it!" - when your puppy learns to drop the ball at your feet;
2) "Give it!" - when he learns to place the ball into your palm.
It is better to start with the second. It doesn't matter - squeaky or non-squeaky, it should roll on the ground and bounce, and your puppy should like the ball. Find a smooth, sloping down surface somewhere in the park. Push it gently down. Your puppy will chase it, play with it and finally will bring it back to you. But, you shouldn't take it - let it roll down the slope again and again, your pup will bring it back to you again and again. One moment (just don't make him bored of it) pick it up. Let him see, that the ball doesn't "run away" only when it is in your hand. When he, actually, will attempt to give it to you - exchange the ball for a treat by taking the ball with one hand and giving the treat with the other. Starting with a gentle push at the ball allowing it to roll down, continue with throwing the ball down the slope later in the course. Your dog should place it into your hand.
When you teach him "Drop it!" - start with kicking the ball, not throwing it (you kick it or you throw it - that is later, it shouldn't be different for him if he knows it well), so, the command would be associated with your foot first. This way it will be easier for him to differentiate these two commands later.
One of the handiest tricks of the trade a veterinarian taught me was how to get a dog to open his mouth and drop something.
You gently reach in and push down on the tongue with your finger. This triggers a reflex and the dog opens his mouth. Very easily done if he is holding a ball between the teeth.
When Hans would bring the ball back to me, and hold it between his teeth, would reach in, push down on this tongue, and the ball dropped in the open palm of my other hand. At the same time I would mark it with, "Give."
It took no time for him to figure out that I wanted him to drop the ball in my hand.