Basically, Spotify can see what's hot, hat's upcoming and so on and so forth. Viral charts are also made up of things scraped from the net such as blog posts, Reddit posts, shares on Facebook, Twitter, Instagram, WhatsApp, ... so sharing the release on as many social portals as poissible and getting those people to share as well will help.
Getting your fans to follow you, and save your track to their playlists and libraries is also very important. These are all simple steps to take to get your music out there and also get it noticed by the curators at Spotify.
There are many other things you can do. So, don't be afraid to really market your track. It doesn't need to cost alot, be smart about it and be consistent.