The waiting-on list is for those tasks that are important to you but that someone else must do. Keep a log of such tasks as soon as you’ve delegated them, or if someone has volunteered to do it. This technique is further strengthened if you log the dates that the task was assigned and its agreed deadline. Avoid creating more admin for yourself by being picky about what is on your waiting-on list (not more than a dozen). A lighter version is to tag all actions for others with ‘WO’ so it is logged, and you can circle back and chase up periodically.
Source: learn.filtered.com