I have successfully beeminded things like “don’t pick your cuticles” or
"don’t swear". The way I did it was a do less goal, set up extremely
generously at the beginning, like “50 times a week” as my initial rate, and
then I beeminded 1 each time I caught myself picking/swearing. I used an
Ablet, which is a knitting row-counting bracelet thing but it lets you save
a count on your wrist without having to pick up your phone. If I were
doing one today, I’d use a Life Counter Ring.
http://www.critsuccess.com/index.php/lcr-counter-ring.html
The key to my success was to adjust my rate every week, and use
retroratchet to reduce my safety buffer.