What I do is just think about the concepts provided and ask questions about the concepts to myself. I then answer those questions and the answer becomes my thesis.
Also, I’m stealing the theme from Wizjaro for this example.
Eg. How is the theme of control relevant to your text?
Ok. So what is control? Control is having power over things. What things? Themselves, other people, monarchy idk. Do humans have a desire for control? Humans always have the need to be in control of their lives. Some human beings have a strong desire to have power over others.
That’s it. Ok, thesis time.
Humans are megalomaniacs that desire to have power over all things, including themselves and others. This is seen evidently in [text], where [character] does [x] to [whatever the character does to enforce control]. And then the rest of the paragraph continues.
Probably isn’t the best thesis, as it was from the top off the top of my head with no severely in-depth thinking, structure or thesaurus dot com. But I’ve made my point clear. Just ask questions to yourself about the themes involved, and you will eventually generate something you could use for your thesis. Hope this helps!