My takeaways from CBT:

1. Don't give your opinions (e.g. probabilities, value judgements) greater weight than other people's, despite having access to information (your running inner speech, for example) that other people don't have. I'm not confident of my justification of this practice, so I won't put it here.

2. Do respond to inner speech, arguing with it using all the rational-argumentation techniques at your disposal. For example, "I'm a terrible person" should not go unchallenged (and the claim is very susceptible to rational challenges: fundamental attribution error, overgeneralization, doesn't admit the possibility of change, et cetera).

3. You will feel better if you do something, even if starting to do something feels horrible. Trying to do nothing in order to "recover willpower" or "get in the mood" doesn't work.

I would recommend "Feeling Good" by Burns, as an (somewhat verbose, but easy-to-read) introduction to CBT.