This is possibly one of the most asked questions from artist at the moment. Getting your music discovered is becoming harder than every.
Here is some advice from Spotify CEO, Daniel Ek, on this topic.
The easiest way today is to convince people to put it in their playlists and share it if they like it. Both of those channels are massive and they can lead to to more promotion through our viral chart, through Discover Weekly, to being featured as a new release, etc. Spotify is a democratic system in the sense that if people really like it, and the “vital signs” as we call them are good, then the system will figure it out and spread the word.