For critical and overall... fiddly things, we've grown into a culture of writing down reviewable plans and possibly executing these plans in pairs.

We tend to go ahead and either use a runbook, or whatever experience we might have, to setup a pretty detailed plan of what to run on which systems with which purpose. You can then throw these plans at someone else to review. Sure, it takes an hour or two more to setup a solid plan and waiting for a review takes time as well. But this has turned into a great tool to build up experience in weird parts of the infrastructure.