There are quite a few OpenShift Morsels available already, so let me put them on a single page for a faster search and browse.
Short knowhow transfers, some small tips how to setup something or learn about OpenShift client.
Commands that can be useful on daily basis and not necessary fit other topics.
Users, roles, permissions
Exploring the parts related to security of OpenShift and Kubernetes.
How to find what is wrong with the application? There are quite a few places you can have a look at.