Note to self: When creating Custom Report Types don't include fields from managed packages that are only installed on the sandbox. It causes your Demployments to fail.
Start Here
If you don't yet fully understand the power of Custom Report Types start with watching this excellent video Learn Salesforce Report Types in 10 minutes!. And some of those tips are also covered in The Hidden Functionality of Custom Report Types - Admin Hero.
Annoyances
- Taking fields off the CRT is stupid. You have to go to the end of the list of fields in the right hand side box, then drag the field to the blank space. Weird. Stupid.
- Try setting up Custom Report Types in Lightning Setup. It's a window of the old old Salesforce interface inside the old Salesforce interface inside the new Salesforce interface, and it just looks shocking.