One of the first fundamentals to learn the golf swing is the proper grip and rightfully so; it is the sole connection to your body and the golf club, you must have a grip within the accepted parameters in order to play golf effectively.
However, even before the grip happens, there is a less talked about fundamental which deserves just as much if not more attention, especially for people who really want to get good. This crucial fundamental is the connection from your body to the earth. Yes Footwork!! First let's define footwork as it is not merely what the feet are doing, but it also encompasses the motion of the ankles, knees and pretty much the whole leg. Most amateurs have the improper footwork. Improper footwork is the one of the first things that should be looked at to diagnose any swing flaws. Not using your feet correctly can lead to swings that are off plane, early extension with the body, casting, inconsistency, lack of balance, and improper body trunk rotation to name a few. Putting it plainly, you're going to suck if your feet don't work right! It's funny how many golf lessons I see online from top instructors try to teach certain movements without addressing how your feet should work when the solution could very much be in the feet! For example, you will find many youtube videos on instructors trying to teach hip depth, shallowing out the club path and keeping the tushline without addressing footwork!! Good luck, never gonna happen!
The Feet roll and everything else glides
In the correct foot action, your feet, ankles roll. This causes your hips to actually do what I call is gliding. When your hips glide you are much more able to get into the "Slot" much more able to get into balance and get into all the positions that the top ball strikers are getting into. I wish I had some reference video links I can point you toward, but in the meantime look at this photo of Kevin Kisner. The best way I can explain it is to imagine a skier skiing down a mountain with their skis parallel carving side to side. This is how your feet and ankles should work. This motion is highly more different that arbitrarily "Shifting your weight the front foot." So, if you really haven't paid any attention to what your feet are doing in the swing, you'll see how much if affects your golf shots' accuracy and power! Do your feet work like this?