One the problems i see from most of my students swings is bat lag to the ball. Bat lag is the position where the bat is prior to entering to the strike zone.
At bat lag your weight should be going into your front side and your hands should be out in the center of your gravity. The bat is mostly parallel to the ground. I always tell my students if your gonna use a hammer to hit a nail , wouldn't you hammer that nail out in front of you where your strong. This is where the term staying behind the ball comes in. The bat will release underneath the hands down the line of the pitch.