For starters you will need a thesis. A good one would be, "In a series of posters, the British government employed a variety of persuasive techniques to convince people to join the war effort." Then go on from there, I'm currently doin this myself, so I will be working it out myself and then get back to you.
In the time of the world war 2, propaganda is everywhere which helps in complete analysation of the details. All the commercials were taken into consideration which were used effectively in the world war 2. Different types of techniques were used in each war which also determined the effectiveness of the techniques. There were leaders of the allied forces which played an important role in the world war 2.
Sorry man, you shouldn't be on here asking for people to write your essay for you. You got it though. Just make a good outline for each paragraph and the rest will flow. Trust.
