To establish better timing with the bounce and to better see the ball to your racquet, say (either to yourself or out loud in practice), “bounce” when the ball bounces and “hit” when making contact with the ball.
Maintain a balance and centered position (with the core of your body centered above your hips) and a still head position (a quiet upper body) when moving left, right, up and back to hit a ball. It is hard to see and track a ball when your head is bobbing up and down.
Focus on reading the lettering on the ball (which can be more difficult for balls hit with a lot of spin).
For groundstrokes, keep your head down and focused at the point of contact through the follow through and the finish of the stroke. Lifting the head too early is a major cause of mishits.
For serves and overheads, keep your chin up and head and eyes focused on the point of contact until completion of the stroke and follow through.
Position your eyes and head at the level of the ball to better see the ball for volleys. Try to see the ball through the strings of your racquet.
Having trouble seeing the ball in the sun with your serve? Use your tossing hand to shield the sun.
As an alternative approach for watching the ball, take your focus off the ball (at least attempting to track the ball from start to finish) and fix your visual focus on your contact zone. Visualize a large window spanning the court in front of you at a comfortable arm’s distance and use your strokes to prevent every oncoming ball from getting past this imaginary window.
Similarly, go from a “soft” to “hard” focus. It’s difficult to maintain a “hard”, intent focus on the ball from start to finish (from the point at which your opponent makes contact with the ball to your point of contact). Instead, initially establish a soft focus and then narrow your focus on the ball as it approaches your point of contact.
Of course, anticipation and your ability to recognize hitting cues from your opponent and likely hitting directional patterns, helps you get a “read” on the ball for better sightlines and vision.