There are basically two different types of rhetorical essays. One is an expression of your opinion on a text you read, such as a book or article. This is sometimes called a rhetorical analysis essay. A regular rhetorical essay can be about any subject, but provides a line of reasoning, a summary of the line of reasoning, an explanation and clarification of what you think it means and why.
A rhetorical analysis essay is different than a book report. In a book report, you may give some background on the author and give a summary of what the book was about. The author's viewpoints and your reaction to them are not usually part of the report. That's where a rhetorical analysis essay comes in and putting into your own words what a text meant to you can sometimes be difficult. Start with the author of the text and tell a little bit about that person and how you may feel toward the author. Then summarize what the text was about and whether you think the author expressed his ideas adequately and if not, why. Describe points about the text that the author could have made better or clearer.
With any essay, it is important to remain succinct and not to wordy. After all, it is an essay, not a book. If you ramble on about your opinions, people will not want to read your essay. You have to give reasons why you have each opinion and the reasons have to make sense to the reader. For example, you can not just write “I'm apposed to the healthcare plan.” You need to go into reasons why you are apposed to it, which may involve a little research. Don't be afraid to cite references if you have to do some research. References give the essay credibility and will let readers know you are knowledgeable on the subject you are writing about.
Essays are usually written in a formal format. Avoid slang terms and a lot of unnecessary words. Keep things precise and use proper spelling and grammar. People do not like to read essays with words misspelled. It is distracting and it reflects on your writing skills. If you write with proper spelling, correct grammar and are able to get your points across in a precise and convincing manner, you have the makings for an excellent rhetorical essay.