it is a practice.
like. not a few weeks kind of practice, but rather 12 months kind of practice.
people are different, but what worked for me was sitting down for 10 minute "meditation" sessions.
my mind is racing all the the time during, i get maybe 1 - 3 focused breaths.
It helped me to recognize a category of any thought that popped up, and then just try to let it go.
It helps me detach and distance myself a bit from the thought itself. Something i find very helpful when it comes to both the symptoms of ADHD but i would guess also in general.
Give yourself time. To break from the tracks of the mind is a slow process.
Something you keep returning to for safety, for familiarity.
Give yourself time to learn. to change that pattern. It doesn't always work. Sometimes you forget for a period of time.
thats ok