Ask HN: What would you want to see in a DevOps monitoring handbook?

Some background: I'm an Ops engineer in a Small UK ISP. I joined when most the team was new, and the previous Ops engineers had moved up to higher positions. Because of this most our systems were dated, and I've had to learn a lot to bring us up to modern monitoring standards.

I've been wanting a side project I'll enjoy for a while, and I get asked to train new hires at work on our stack, so I was thinking of writing something anyway. I'm not looking to make a lot of money, but maybe printing or selling it as an eBook could help pay my DigitalOcean bills.

The stacks I'd be writing about would be: Icinga2, Grafana + Graphite, rsyslog/logstash, Graylog, Collectd, etc. As well as tech I'd cover the general methodology behind running a complete DevOps monitoring setup, not just a configuration guide.

What kind of things do you think would be worth including? Whether I write it for profit or just for new hires, I'm going to write it anyway, so suggestions welcome.