That's a lot of parental advice to digest in one sitting, so let's recap the highlights of what we've talked about. The life cycle of a typical parent goes something like this:
You have a single zone, with all of your hosts in that zone.
You break your zone into a number of subdomains, some of them in the same zone as the parent, if necessary. You provide CNAME records in the parent zone for well-known hosts that have moved into subdomains.
After a grace period, you delete any remaining CNAME records.
You handle subdomain delegation updates, either manually or by using stubs, and periodically check delegation.