How to write up a hypothesis: the good, the bad and the ugly

Alas, not everything received comes close to even this liberal standard. Since I joined the Editorial Board I have read about 130 submissions to Medical Hypotheses. They range from exciting and insightful papers that might be substantial advances in their field, to complete rubbish. I want to lay out what I believe to be the essence of the former so as to avoid having to read so much of the latter.