The FUNDAMENTALS..... Easy Peasy
The golf swing is not a cognitive action, its a reactionary movement. This means we aren't fully aware of every minute action we are performing, we are reacting to the ball and we can be forgiven for any unwanted movement or bad shot that occurs from our swing as mostly is an unconscious action.
The fundamentals are all pre-swing elements to the golf swing and we're fully aware at this point and more importantly we can take the time to check.......
The grip is correct
Our ball position
Face and body alignment
You will be amazed at the results if you master the above skills. Compared to changing your swing where we have to break down a subconscious movement pattern and inject a new one, your grip, stance and alignment are really important to how you will move the club and where the balls going to go.
The best in the world spend lots of time making sure the fundamentals are in check with some simple drills and range setups. have a look...
The above picture is great for ball position and alignment. Just by using two alignment sticks when you practice will help build a solid foundation of alignment and ball position, so crucial to help anyone perform there best.
You could even take them out on the golf course during a social round to check before and after your shots.
I HATE YOUTUBE for golf coaching as it negates the learning processes but you cant go wrong with a grip video. You could invest in various cheap and effective grip training aids that will improve your grip.
The little things can have the biggest impact to your game so don't neglect them.