Contrary to popular belief, lifting the head – as in, turning it too early away from the ball and toward the target – does not cause topped and thin golf shots. If the head comes up as a result of your upper body rising, that’s a different story.
In reality, raising your spine angle prior to impact is the root cause of many (if not most) topped and thin shots. Coming up and out of your posture pulls the club away from the ball, and you strike it with the bottom of the clubface.
The key is to maintain your spine angle from setup to impact and into the follow-through. A great mental cue is to imagine your shirt buttons lined up and pointing down toward the ball at address, then returning them to the same spot at impact. This will promote a proper motion going back and through in which you rotate around the spine rather than lifting.
Remember: Buttons over the ball for solid contact.