How we change what others think, feel, believe and do
Define a short phrase which enthuses people into acting in the way that you seek. Keep it simple.
Use the slogan all over the place. Use it in speeches. Put in on posters, flyers, adverts and so on. Use it by default as a header or footer in documents.
Expound upon it. Discuss what it means and what people should do as a result. Use it to beat your opposition and legitimize your actions.
'Yes, we can' - Barack Obama, 2010
'Labour isn't working' - UK Conservatives, 1979
'Open your eyes' - Greenpeace
'As long as there is injustice in the world, there will also be Amnesty' - Amnesty International
'If you think education is expensive, try ignorance' - Derek Bok (US educator and lawyer)
'Fair trade, not free trade' -- (on peace button)
Keeping slogans short and simple makes them memorable, which holds them in the mind and so perpetuates their force. Repetition hammers them home, not only making them easier to recall but also, when spoken by authority figures, giving them legitimacy and requirement.
The words do not have to make immediate sense, but they should always seem plausible. The feeling they create is more important than the rational meaning.
Slogans can compete with one another. Sometimes a political contest will hinge upon who has the better slogan. A great slogan can deliver the knockout punch, particularly if it is delivered well and with good timing.
Slogans are used in many situations. Advertisers use them as taglines. Politicians use them. States use them (eg. 'Florida: The Sunshine State').
Nazi Germany used subtle slogans such as 'The Jews are our misfortune' and 'To each what he deserves'. In '1984', George Orwell creates the slogan 'War is Peace; Freedom is Slavery; Ignorance is Strength'. These may seem curious reversals but this is a part of the power. Each point can be argued to be true. The slogan is then used as a guiding force by the government to excuse all kinds of atrocities.