We’d recommend posting on forums about your station, specifically those specialising in either voiceovers or general Internet Radio topics. Secondly, Facebook groups are great for this kind of thing (i.e. https://www.facebook.com/groups/Internet.Radio.Station.Advertising/) and have been known to increase traffic.
Another good way is to invest in advertisements, find a theme or a “selling point” for your desired demographic and run with it — create an ad campaign somewhere people will see it, forums often allow you to advertise online at affordable prices. You should add your station to numerous directories too, a notable mention is BroadcastingWorld (http://www.broadcastingworld.com/stations/).
Advertising a station is essentially blood, sweat and tears. But if you are providing good, consistent and interesting content — you’ll get there in the end. If you need any more tips, let us know. Our team is full of them.