I have observed a lot of players messing around with tweeners (hitting between the legs), using the opposite arm (for example, left hand when they are a righty), and other tricks.
Honestly, I’m not sure why. There is so much to be learned and gained from concentrating on the fundamentals. In my experience the best players stay focused on mastering the fundamentals.
By fundamentals we’re talking about the blend of technique, mental toughness, strategy, and fitness and nutrition.
For beginners, technique involves grips, proper movement, ground strokes (forehand, two-hand or one-hand backhand), serve, volleys, and overhead smash.
Check out the posts and links on this site for lots of great instructional material on fundamentals.