It all depends on the genre you are trying to find music for. I have curated for Hot 97 Who's Next - a big hip hop radio station out of New York since the 1980's.I have listened to an exceptional amount of good hip hop, and I know what stands out among the good music. If you have a genre that you're most familiar with, stick to that.
Here's an expertly curated Spotify Playlist by Me. I just put it together yesterday. If you can listen to 22 songs, even just half listen, you will notice a few key things that stand out about all these great songs.