Hips can move laterally or rotate and its hard to do both at the same time. if you can start with the hips moving laterally towards the target, then, they can stop - brace - and then they can rotate.
If you find that the the shots are going right (for a righty), continue to delay the rotation, keep moving forward, but ensure that your upper body is not moving forward at the same rate. If you are 'stacked' at impact, the angle of the club coming down is steep and there's a good chance you'll hit it right.
The amount of rotation vs. slide is somewhat dependant pattern or swing style. A guy like Adam Scott with a very high arm position who likes to keep his arms in front of his chest will have less slide and more rotation than a guy like Charlie Wi, who would continue to slide forward and delay the rotation for further in the downswing.
Keep in mind... when you slide forward, the hips ARE Squaring to the target line - its a product of the knee action. Your conscious effort is to delay the rotation.
there are videos on youtube talking about the hip action in the golf swing.