Watch the ball onto your racket
This may seems obvious but it’s amazing how many people don’t do this. Professionals do this but I rarely see it when I coach “normal” players.
It takes a lot of confidence to watch the ball all the way on to the strings, most players want to look where they are hitting the ball. For example, if they are playing a volley drop what I normally see is that they will watch the ball through the air, and right before impact they move their eyes to look just above the tin where they want the ball to go. This often results in a poor shot, whether the shot hits the tin or they slightly mis-hit the ball.
You must have faith that you can control where the ball will land without looking as you hit the ball. This is exactly the same as a striker in football. Look up to decide where you want the ball to land, then head down and strike the ball, focusing 100% on the ball hitting your foot.
So, watch the ball on to your racket strings and only look up once you have made contact with the ball.