By far, the best way I've discovered new music is through radio. Find a station with producers that you jive with and this will be a treasure chest. I was lucky enough to grow up in Athens (GR), where radio is really, really good. A big disappointment happened when I moved to SF (which, aside of KCSM - a great jazz radio - is a music radio disappointment). I was lucky to come across KCRW from LA, perhaps the best radio station in the US. I've been a member since before it became my local radio station. Couple other notables are The Current (KCMP) and KEXP.
The other big (meta-) source is surrounding myself with people with similar (or not so similar, but still interesting) music tastes. I've discovered a TON of music like this.
Yes, I've discovered a few things from algorithmic recommendation systems (e.g. spotify). But: (a) the quality of the recommendations hasn't been even close as good, and more importantly (b) there is zero emotional connection (i.e. like saying "oh, this is the band that Eleni showed me when we were camping in Yosemite").