I believe the way that we used to implement D365, D365FO and D365BC needed to change. In my last couple of projects I have been learning to adopt an agile approach and this has proved successful. As part of that I have enjoyed some great online training in using Scrum as an agile tool via Customery and then also used the resources on Scrum.Org which lead to gaining the professional certification below:
I am working on a blog post to cover how I understand Scrum and also how & why I find it useful when implementing Dynamics 365 applications.
EDIT: Blog post completed and available here: http://www.rustongroup.com/d365fo/using-scrum-in-the-context-of-d365/