Impact can be thought of as the moment of truth. It is important that the at impact the left wrist is flat, the right wrist bent and the right arm bent in the process of straightening.
To improve your impact conditions start by making small swings around the green. Since impact is the same for all clubs and for most shots it helps to learn from small swings first. Keep your mind on your hands as you move the flat left wrist past the ball. There should be a slight downward strike. Keep the acceleration even and try to feel the pressure against your right index finger. The feeling of dragging a mop might be a good image.
Once the basic motion or chip swing is learned proceed to the half swing where the bent right arm is parallel to ground in the backswing and the bent left arm is parallel to the ground at the follow-thru. There will be some pivot incorporated as it will provide more power but the impact conditions and feels should be the same.
The full swing is a finish oriented motion using a full pivot for maximum power. Be sure to hold a balanced finish position with the hands over the left shoulder. If the impact conditions matched the previous swing patterns the the ball will have maximum velocity and fly straight to the target.