Leave your watch/clock at home. It works!
This is similar to my well tried and tested method.
The more you watch the time, the slower time moves. But if you haven’t looked at a clock for a while then oh wow another 2 hours have passed.
My tip is to virtually not look at the clock the entire day BECAUSE THERE IS NO NEED TO!
My time schedule on yom kippur does not consist of hours and minutes but stages of davenning. I say to myself the time now is eg early part of shacharis or middle of musaf or towards the end of mincha etc. This way I find the day moves much quicker.
If this tip helps anyone else then it was worth the time to post it.
Wishing everyone a ??? ????? ???? and an easy fast!