Byron Katie has a very effective way of finding beliefs and generating statements for inquiry:
Write down one of the things you are most ashamed of in your life. Something you like the least to share with others and yourself.
Then, write down a list of what this means.
Say the initial statement is that I lied to a friend. And that means that I can’t be trusted, I betrayed our friendship, I am a lousy friend, he wouldn’t want anything to do with me if he knew, I am a bad person, I am confused, I put myself ahead of others, and so on.
Then select one or more of these that have the most charge, or do all of them one at a time, and take them to inquiry. Is it true? Sure? What happens when I believe that thought? Who would I be without them? What are the reversals, and the genuine truths in each of them?