Resources For Releasing New Music
For DIY Artists
Streaming
How to promote via Spotify and get on official playlists.
https://artists.spotify.com/help/article/pitching-music-to-playlist-editors
https://artists.spotify.com/help/article/promoting-music-on-spotify
Growing Your Band
Jesse Cannon wrote a good book about DIY music promo and building your band. He recently started putting out videos as well.
https://www.youtube.com/playlist?list=PL0i-5Ujnd4VVckEVaE1_RUcLzPF8U680K
Bandcamp
In addition to streaming services, bandcamp is a good place to add your music (which you can do yourself). You can add tags to your album so people who are browsing can discover it.
Youtube
Visuals are super important. For main singles it's a good idea to release a full music video done with a professional. If you don't have the budget for a music video, shooting something on your phones in a creative way can also be effective. At the minimum, I'd get someone to make a lyric video or visualizer with your artwork.
Submithub is a place where you can submit the song to a bunch of blogs and playlists to get more press. It's somewhat hit or miss but you can narrow it down by genre to find blogs that fit your style.