- try finding different artists under the "similar to this artist" thread on the artist's page. with this tactic, you can find differents bands and artists like a chain.
- some youtube channels (non-official, uploaded by fans mostly) create playlists or upload songs under the same genre. also keep an eye on the recommendations section. (I have found many great artist via this method, after discovering someone on youtube, I find them on spotify and add to my playlists.)
- soundcloud + mixcloud are also great sources for "discovering new artists and bands"
- be a stalker, truly. check the other people's playlists and profiles. some people on spotify are very charitable indeed, I have found many people around the world with tons of great public playlists on their profiles.
*I can also share some music/playlists/sources to find with you!