I wonder if buying the nail file first would make this even easier. Get your subconscious invested in the idea that you're going to need the nail file. Make the consistency principle work for you: in order to be consistent with your past actions, you have to stop biting your nails.
Also, congrats!
Having tools like the nail file helps under good conditions; the hard part is not relapsing when under stress/other triggering conditions.
This is the public group instrumental rationality diary for the week of July 23rd. It's a place to record and chat about it if you have done, or are actively doing, things like:
Or anything else interesting which you want to share, so that other people can think about it, and perhaps be inspired to take action themselves. Try to include enough details so that everyone can use each other's experiences to learn about what tends to work out, and what doesn't tend to work out.
Thanks to everyone who contributes!
Last week's diary; archive of prior diaries.