Ok, I am back.
This is so tough to put into words, but let me see how I do.
If you are sitting in your office, and you rumple up a paper into a ball and go to throw it into the garbage can, it doesn't matter if the can is to your left, your right, or straight ahead. The throwing motion you use is the same, you just aim in a different direction.
Now, in this office, imagine you have one of those fancy decorative globes that you can spin on either axis.
Now you move your hand in the same forward and out brushing motion but you brush on different parts of the globe to make it rotate in different directions. The motion of your hand is the same, but it is just hitting the globe in different spots, and brushing it in a different direction due to how you line up to it.
Now as you are brushing the globe, you keep moving your hand the same speed. But at first you ever so slightly just barely graze the globe with the tip of your finger. It won't spin much no matter how fast your hand is moving because you are not hitting it solidly enough, so you, keeping your hand moving the same speed, just brush it a little more solidly, and now it starts spinning better, and you brush it a little more solidly and it spins a little better. Sooner or later you will get to the point where the globe spins as fast as it can with that given hand speed.
Now once you find the right amount of brush which translates to the maximum rotational speed, if you continue to hit it more and more solidly, the spin will be slower, but you will actually be hitting the globe so solidly that it will not only want to rotate about its axis, but move entirely in the direction that you are hitting it across the office floor. That is adding pace to the serve.
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Ok, so now, you know where you need to hit the ball to make it go where. You hit the left side of the ball, it goes right. Hit the right side, it goes left. Hit the top, it goes down. Hit the bottom, it goes up.
So before every serve you hit, you decide, first on location, then on spin. Location, how much topspin, how much sidespin.
Now you know where to hit the ball, and which direction your swing should be going as it attacks that location on the ball.
All that is left then is to go out and practice it, and screw up a billion times until you get the hang of it.
As far as where to toss the ball, while you are learning to vary spins and speeds, just toss the thing straight in front of you every time.
Once you get the hang of putting different spins on the ball then you may find that moving the toss gives you a better angle on a certain attack route, and you may decide to change, but personally, I would just keep the same toss for everything.
In addition to not being readable, keeping your toss the same is one variable that you can eliminate. Translation: One less thing that can go wrong.
J