One small tip that has helped me is to make sure that the part of your trigger finger from your knuckle to your middle joint is parallel to the gun. This allows the rest of your trigger finger to pivot straight back instead of at an angle which tends to push the gun to the left.
This is sometimes referred to as having "too much finger on the trigger". On guns that have interchangeable grip inserts (most if not all M&P's do), you can choose the insert that helps place the trigger finger at the correct place. Too narrow a grip can result in you having too much of your trigger through the trigger guard so that instead of pulling straight back, you tend to push the gun to the left.
Interchangeable grip inserts, besides making the gun more comfortable to shoot, are also very important in controlling the trigger finger position on the trigger.
If it were me, I would use the grip insert that allows for a comfortable grip, but one that also helps position the middle part of the trigger finger parallel to the gun so that the tip of your finger can pull straight back.