I was thinking of creating an anonymous ticketmaster account using public wifi since they block VPNs and just have them email me updates, but they required a phone number for the sign up so I scrapped that idea.
Edit: I decided to sign up for songkick as someone else here mentioned. It seems pretty polished and its entire purpose is concert discovery. It never asked for any unnecessary extra information either such as first and last name and phone number, just an email and a password and boom.
Actually it's super easy.
Step 1: be poor
Step 2: come to terms that you don't have, and likely will never have, enough disposable no income to afford 50 dollar tickets to a concert
Bonus optional step 3: be poor enough that you'll be unlikely to live in a city where musicians will come, even if you found some money. Then you definitely won't have gas money to drive there and see them. :)
It's fool proof.
I subscribe to email newsletters of local venues and production companies as well as a few of my favorite bands.
It usually goes "Cool! That band is gonna... Oh it was last week... Fuck..."
Yep they often have mailing lists.
And Bandcamp if the artists are on there.
Their website. I don't have that many favorite music artists. Checking them out once a year to see that they won't be performing anywhere close to me satisfies this desire 100%.
Pick up the local paper / zines / newsletter and check the concert listings.
My hometown used to have a message board for concerts, too, but it was small enough that one person (or the same twenty people, in reality) could go to every single concert in town, because there were never more than two in a given week.
I receive tons of marketing emails from companies like Ticketmaster, LiveNation (or whatever it's called, etc, because I've bought tickets online from them in the past. I don't mark them as spam because I want to catch shows that interest me. Oh, right, someone mentioned that venues also send emails. I get those, too.
spotify usually has a notification for that, or it'll be on the artists page
I follow artists I like on twitter without having an account, I use the Squawker app for that.
If you use YouTube for music it tells you when the band you are listening to is doing a concert
Not sure about your area but where I'm at a ton of smaller venues are using the dice.fm app for ticketing, it also allows users to follow venues/bands for upcoming shows.
Bandsintown also tracks bands on tour & could be useful though I get the feeling it's better for tracking bigger bands/artists.
Slightly old school but also keep in mind lots of venues/promoters still have email lists you can subscribe to for news/updates.
Beyond that I still keep an eye on Facebook/Instagram for keeping track of those things (I know that's not the answer you want sorry), a lot of times that's what the bands/artists are actually posting to.