In my junior year in high school, I was very fortunate to learn about the techniques of propaganda. Mr. Williams gave us close to ten different techniques that could be used to sway public opinion. We even planned our own propaganda campaign.
Over the years, I have remembered a few of these techniques. Once you have learned these techniques, it is not hard to spot them: glittering generalities, association, the bandwagon, And others.
At the link below is a film of many years ago. The techniques are the same; only the cast of characters and modalities have changed. I highly recommend this film.