One thing I learned early in my teaching profession was to take tilters which is the majority of golfers who are struggling and learn how to make them turners.
If you slice the the ball and/or end up on your back foot and never seem to be able to get onto your front foot at finish most likely you are tilting during your back swing. By tilting what I mean is that your front shoulder (left if you are right handed) goes down towards the ball. What is happening is that your shoulders are working in too much of an up and down movement rather than staying level and turning across and behind the ball.
The fix: Try and turn your shoulders more level and make your left shoulder feel as if it is turning straight across your body to a position that is even with or behind the ball. Try this back swing tip out and see if it doesn’t help you make better back swings and hit better shots!!
Do pivot drills in front of the mirror
Place a club across your chest
Get in your posture put club across chest
Arms crossed
Turn shoulders level and over your left foot
That is the feeling of what your pivot should feel like
Practice these away from the course and see if your pivot doesn’t improve on the course and you don’t hit better furhter tee shots