Rhetorical analysis essay help?

I have to write this essay as summer hw. However, my English teacher did not teach how to write a rhetorical analysis essay. I googled around to see how to do it and i'm still pretty confused on how to put it all together.

The question for my essay is:" write an essay in which you analyze rhetorical strategies that Thoreau uses to develop his position."

So far my thesis is: In the book, Walden, Thoreau uses figurative language, theme, and characterization to help develop his position.

I feel like this is the wrong way to write a thesis, but I honestly dont have a clue on how to properly write a thesis for this type of essay. Please help?