Add another network question debugging an issue

[fartbagxp]

You have just provisioned a brand new server and you would like to login to it, via SSH or RDP.
Both are currently failing with a timeout. How do you go about figuring out what is wrong and how would you go about fixing it?

[fartbagxp]

This is similar to I've rebooted a remote server but after 10 minutes I'm still not able to ssh into it, what can be wrong?, but not quite, in the sense that there could be many things wrong with the initial provisioning of the server (ssh server / rdp server not started, not on the right port, firewall rules are blocking, etc).