Start with your visual material. What do you have? What does it say? Is there a connection with the things you'd like to say?
Don't expect to be done immediately. Give it time to grow. Try out as much as you can until you find the right form.
As a Visual Anthropologist I was happy to make use of all the photos that I had gathered during my fieldwork (which also resulted in a documentary film).
During the process of making the Visual Vignette, I initially separated text and image section very strictly. The longer I worked on it, the more I experimented. In the end I arranged the entire text within the images as if it was some additional visual information.
Due to the very limited number of words I had to rethink the very basic messages I wanted to convey. Using my images as the primary communication medium, the research topic became less abstract and much more grounded. I realized that much of what I wanted to explain was actually shown much more clearly in the pictures.
I used the Visual Vignettes mainly as a research communication tool, but also obtained a new understanding of my already completed fieldwork. For my next project I will definitely use it to organise field notes and to analyze my data.