How do you discover new music?

What i do in Spotify is to start with an artist i like, or with a playlist (big ones if you look for mainstream music or user-created ones if you want more underground variety) then dive into the Related Artists page (right below their name) and surf through the musicians i find and listen to the ones with nice pictures or album covers lol

in "Your Library" you can find Spotify Mixes based on the artists you listen the most. It's great and works for me too