This is the most difficult part:
developing the most effective message
Step-by-step explanation:
In the marketing sphere, the most important thing is often touted to be the message of the ad.
If you have created a good message you have a lot of permeability into the market that is otherwise not available to you so much.
In the international advertising front it is important to find something that would speak to people across the planet from different cultures, different classes and different language groups.
Thus the message has to be simple, concise and universal.
Some companies like Nike have done it well with "Just Do It'' which is a great blanket statement.