I mute every "server" permanently, disable all "mentions" (@here, @role, etc) and it stays quiet except for DMs. If there's something I want to see I'll go look in a channel.
I have applied the same measures as GP; if it is interesting/important enough, I will find it manually. (Similarly, I am an administrator of a public server; I regularly remind regulars and other admins that I'll only get notified from DMs.)
For announcement channels that I'm feeling more certain I don't want to miss: I created a server for myself with a channel that has subscriptions to all the announcement channels that I want to be notified about (I also check this manually, but at least it is a custom-tailored feed just for me).
There is no coping with the (..checks Discord..) "4k+" outstanding notifications (and counting) that I am bombarded with. Slightly ironic that the Discord interface can't even be bothered to tell me the exact count; I'm not going to bother.
It used to amuse me to see people complain about @everyone tags. The commonality of it leaves me desensitized these days.
The channels with no activity remain grey instead of white. It's important to me that I discover messages when I have some downtime and am interested in so-called discovery, as opposed to having junk interrupt my flow at times when I am not.
