Saying the impact area is the most important part of the golf swing isn’t exactly rocket science. With all good professionals they may differ vastly in their swings however the impact area is almost always the same. This is because certain rules need to be followed in order to make great contact with the ball.
First of all and most importantly the hands need to be in front of the club face as you make contact with the ball. This is imperative for direction and control. If your clubface comes through first before the hands it won’t matter how good your swing is, you will always struggle with consistency. If you find that you are doing the latter, the best way to overcome this is practice hitting shots with the ball positioned at the back of the stance, keeping the hands forward of the clubface as you make contact with the ball.
Other key indicators of a good impact area is someone who has their left shoulder and left hip perfectly in line as they hit the ball. The hips need to have also cleared to the left with shoulders approximately parallel to the target as you hit the ball. Lastly the eyes need to be focused on the back of the ball with the weight transfer pushing onto the front foot. If all these elements are present within your golf swing, then you will have great consistency and confidence over any shot.
Of course its easy enough to just say to get into these positions, the practical side is unfortunately a different story. Even though I said before that even great professionals have different swings but the same impact area, the majority of us need to still have certain rules that we must follow in the setup and backswing in order to deliver the club to the ball correctly.
Therefore my recommendation would be to firstly master the basic fundamentals and back swing positions and then address the down swing and impact area. Of course the best way to monitor your progress would be to periodically check yourself on video to ensure that all drills and positions you’ve worked on during practice are adding value to your golf swing and not taking away.