If you've observed Tour Professionals' swings on Youtube, you would have seen a very common trend through impact. This is where the hands tend to stay in front of the clubface at impact. This is a vital element in having a strong, consistent impact as it ensures that you're using the leading edge of the clubface effectively through the strike.
Many people when attempting to have their hands in front though tend to address this issue the wrong way round. Most try and keep their hands in front by over emphasizing their arms and hands through the ball causing a drain in power. This drain in power is due to the arms becoming disconnected from the lower half.
The correct way to address this issue and hence achieving this position is through how you sequence up your body through impact. The correct way as mentioned in previous posts is ensure you start the downswing with the lower half by a bumping of the left hip followed by rotation. The important part about this rotation is then bringing the upper half through which leads to the hands staying in front of the clubface.
The best drill for this is utilising an alignment stick and gripping it with your left hand along with the club. Ensure the alignment stick is positioned just left of the left hip. All then you need to do is ensure you start the downswing with the lower half and making sure the alignment stick doesn't hit your body at impact. This will give you the perfect impact position.
If you think this is your problem or need further clarification please don't hesitate to ask.