Currently, items are ordered by due date. However, a To Do list does not always have a due date. There is no way to order To Do items based on the order you want to work on them within a specific date or when they are unassigned to a due date
Thank you for your idea. We do not currently have plans to allow custom ordering to-dos however we will continue to monitor customer feedback on this idea.
In the meantime, it is possible to re-order to-dos based on several pre-set options such as record, summary, or due date using the My work page.