See Zeroing In On The Focus for how to create your statement of synthesis.

Try to craft your title first. This will force you to zero in on the major point you want to make in your piece. If you can't crystallize the general purview of you piece in the title, you haven't done your thinking and don't know what your piece will be like-your title and focus statement have absolute control over the rest of your piece. You can communicate your point in only a few words. See Zeroing In On The Focus for help in conceptualizing your title.