It can be tempting to try to hit the ball straight ahead. But, when you aim straight, you’re actually stopping your swing halfway through. This is called hitting on a rope.
It’s important to remember to swing all the way through the ball, bringing the racket across your body.
Keep in mind that the width of your stroke is equal to the length of your body. I’m 5’9, so the balls path will pull from right to left five feet, nine inches from the double sideline.