Shaping the ball from right to left or left to right is not a difficult thing to do. It can feel like this at first especially if you are prone to hitting a hook or a slice. The challenge is judging how much to turn the ball. For someone who has a predictable slice or hook and haven't had any previous experience shaping the ball, the first aspect would be to just attempt the other direction without trying to control how much.
You can do this purely by rotating or under rotating the club. If you want to turn the ball to the left for a right hander, I would focus on speeding up the club face through impact and letting the right arm pass the left arm. To a hit a slice to the right I would focus on holding the face open more coming through impact. At first it might take a while to achieve this without prior experience but the more you attempt this, the better you can get.
Now to control how much the ball will turn to the left and how much it will turn to the right and also where the ball will start will firstly take a swing path that is fairly neutral. This is because without a reasonably neutral swing path, you will always find it difficult to control where the ball will start.
Now considering your swing path is fairly neutral the way to control where the ball starts and where it finishes is down to your alignment. First of all to control where the ball starts ensure to aim the body (includes your shoulders, feet, hips and knees) at this target. To control where the ball finishes simply aim the clubface at this target.
Once the alignment is positioned the task then is to make sure you swing toward the line of your feet to ensure the ball starts where your body is pointing. If you do this you will start to control where the ball starts as well where it finishes as when your alignment is positioned this way it makes your clubface either rotate more or rotate less thus impacting the direction of the ball in the air.
Enjoy practicing this drill and if you have any questions please don't hesitate to ask.