Your core message should be clear and unique, boiled down to just a couple of words. One way to help you shape a brand message, is to create a couple of alternatives based on your Value Creation, Band Position and Target Audience.
Start by writing down your Value Creation. Then create 4 different messages based on Know, Feel, Think and Act from Target Audience. For example, create a message based on what you want your audience to know. It can be phrased in infinite ways, but here is an example:
Once you have these 8 different messages, which one of these is the strongest? Choose the one that Is the most emotionally inspiring. Feel free to combine two messages and make some thing powerful. Just remember to keep it simple and clear.
From this main message, we can tweak, and adjust it to suit it in different medias.