While I never had the jelly-shaking in my boots reaction. I certainly felt utterly overwhelmed, and lost in a cloud of confusion, at first.
However, I learned about a technique of writing a short description of each chapter. That really helped me organize how I wanted to write a synopsis.
The easiest way for me is to talk about the heroine, then the hero, then a short description of the story itself.
Often, the Happy Ever After is requested. So I will end with that, either a description or the final paragraph itself.
Writing a synopsis in that way keeps everything organized in my mind. If that makes sense...?