The master of to-do lists in medicine is indisputedly Dr. Atul Gawande. Here are his guidelines on how to write these lists: his Checklist for Checklists.
If you want to go deeper, this article by a group of researchers from Columbia (including our revered mentor Suzanne Bakken, RN, DNSc) offers a helpful taxonomy for medical tasks, classifying them as Perform, Assess, Order, or Communicate.