I see a lot of people have a basic rallying skills. Once the rally is neutral it can go either way. What they suck at is return of serve. I see they make simple mistakes. Wrongfooting a lot, picking weird positions and trying to predict. It obviously doesn't work as well as they want it to be.
I'm here to inform some of them if they read forums. People call it trick. It's like a clown show. You have to be accurate and time it well.
The trick is called "Auto-pos return" (you can google it if you want). Auto-pos is used in the game engine all the time. When you're volleying, when you're hitting ground strokes basically from 1st second to the last moment.
In a simple way when you press any of the 3 strike buttons, b1, b2, b1+b2 your player gets closer to the ball like a magnet. You can see it after the point is over. If you hold the strike button your player will move to where the ball is.
And finally how to you use it. The most important one: here it goes in steps:
1. Your opponent is serving. Prepare to press slice button. b2 or fire 2 in the game.
2. Opponent tosses/throws the ball up in the air, press and hold slice button, don't release, don't let go
3. When opponent's racket hits the ball now you release it. NOW!!!
4. if you did it right, your player will move 2 steps where the ball is going. I'm sure you can run the rest of the distance after that yourself.
Note: it's better to use slice button all the time. If the ball is too fast you'll slice it back. if it's slow you can use some other offensive strike.
Source: http://www.intertopspintour.net/forum/viewtopic.php?t=16862
Ninja Edit 1: like richie said, you run after you release the slice button. If there's a moment where both buttons are pressed you'll freeze on spot.