When the pitcher is warming up before the game on the mound/circle you should be watching their movements. Every pitcher is like a metronome. You can time the clicks 1, 2, 3 (release) in your head.
In the hole
Before you leave the dugout, take another look at their movements or if they have any off speed “tells”. Note how they take the ball out of their glove, and where if any pitches look different with grip or spin.
Start your practice swings and timing with getting your stride foot down into launch position. It’s a dance with the pitcher, when they start to move, you start to load/gather/coil. Your foot should land just a few feet (15-20) before the ball crosses the plate (see video). If you’re lucky you will see an off speed pitch and you can get your timing for that as well.
In the box
Turn off your brain and become a robot in a swimming pool. If you don’t have a sense of the pitchers movements by now it’s too late. You will be at the mercy of the pitcher and umpire and your at bat will be reactionary.