Can someone give me ideas on how to start off my propaganda essay?

You could talk about the countries that have used propaganda, how they have used it, in what times it was used, how it's still being used today, when it came about, the effects it has on societies. 

You can talk about the use of propaganda, the effects that it had on different countries (such as during wartime), and what exactly is used in propaganda that makes it effective!
Hope this helped!