One of the best ways to self promote is to retrace how you found other artists. The reason this is important is every genre is different and you probably make the kind of music you like.
Another way to promote is to be different. It may be tempting to follow trends, but originality is very important for relevancy and narrowing competition.
The last advice is go to the source. Record labels, managers, influencers; Don't beat around the bush. Usually the music industry has key people that "gate keep" and scout talent.
There are a lot of really talented artists that simply can't get on the surface of culture. That may be by design. We accept artist suggestions at rapindie@rapindie.com.