I am by no means an advertising expert, though I have some experience in political communication. Corporate communication is often easier as there often is no one that will answer. In political communication the discussion is an important part of the effectiveness of the message.

In my experience it is best to start by questioning yourself:

• What do you want to say? One sentence, please.
  
• Who do you want to tell it to?

Then look at the surroundings:

Suppose you get viciously attacked. What space do you have to answer? Will you be vilified without getting your point across? Then you might want to play it safe, and dot the i's. Or will you be able to send a representative every time that can hammer in your one sentence? Then you might want to leave lots of room for attacks, as long as your answer every time is your one sentence.

Now you have an inkling of what you want to say, who you want to say it to, and how you want to say it.

Sweden's finest (and perhaps only) collaborative, leftist e-newspaper Synapze.se