According to britannica.com, propoganda is the "manipulation of information to influence public opinion." It says what you want it to say, usually making you look good and your opponent bad.
Wikipedia has a very good article on propaganda. Read it.
Once you have an idea of what professionals are creating, you can try making some of your own for an organization you are involved with, a cause you want to fight for, or just for fun.
To create propoganda, you must first have a target audience. You must understand this audience and be able to predict their reaction to relevant ideas and combinations of ideas. The material you have to work with doesn't need to be truthful, just convincing. If it doesn't matter who in particular you need to convince, just numbers, as in a political campaign, you may wish to target a group that you feel may be the easiest to convince.
If you read the wikipedia page, you will have a good collection of techniques to try out. Certainly not all will be necessary for your project, and you do not want to overload your piece with too many ideas, but it is a good idea to consider all of them to see what will be the most effective for your target.
Where you place your materials can be vital to the success of your campaign. Make sure your materials are placed where they can reach your target but (if need be) not be in the way of something or someone that will remove it before the target is reached.
Once you come up with an idea and means of distribution, do a reality check. Questions to ask yourself include:
Some groups like to tape fliers up in bathroom stalls. Everyone that enters the stall will see the flyer and may be your captive audience for at least a few seconds as they evaluate the flyer to see if it is worth looking at further. Since you have such little time to get them interested, many bathroom fliers have a large picture or large bold text, are colorful, or in some way draws their attention in. It is not a good idea to include large blocks of text in these because most people are not going to sit in the bathroom for an extended period of time just to read a flyer. They will either ignore it or take it with them to read later, which reduces the effectiveness of the flyer since it reaches fewer people.
http://www.answers.com/propaganda http://en.wikipedia.org/wiki/Propaganda