Self release tips:

Invest most of your effort in your production, make something unique to you

Put serious thought into your cover art / overall branding

Get Distrokid or any distributor and learn to distribute yourself - always distribute a few weeks in advance

Set up a bandcamp / website and make sure all music is available there as well

Build a community of artists - reply to tweets, comment on sc (be genuine), be active in discord / groups / streams etc

Become useful, share knowledge, help connect people with different skillsets

Maintain ownership over most or all of your discography. Only sign to labels if it will be a very significant boost for you. Be extremely wary of compilations.

Break down larger bodies of work into a few singles when releasing (you can redistribute them as part of an ep / album)

Singles outperform everything else (unfortunately) - make sure to submit them on spotify for artists when you distribute in advance.

Make sure all of your social media pages link out to your music / other pages

Actively show support for people you think are doing the coolest shit, especially if you know them personally. Don't overdo it, but using your platform to lift up others will be reciprocated.

But seriously though, the music will speak above everything else. If you put something out there that inspires people they will tell their friends about it. It's truly a matter of pouring your heart into something, and then waiting for the right people to stumble across it.