You're right, just having a Twitter or Facebook is not enough. You have to be very active by sending out tweets and befriending other people. Make some videos and upload them to Youtube and other video sharing sites.
If you don't know to do any of this then you can easily hire someone else to do it for you. It's pretty cheap these days.
I think the best way to promote a musician is by social media. There are few ways of doing it. Inform your friends and ask them to like it on social website. Use of internet to the fullest. You get very effective and quick response. I found one more way. I used it to promote my work. Click on the link below. I hope this will help you.
If you are interested in social networking sites, then i suggest you just try Facebook, twitter & you tube which is so famous in the overall world.These sites give you a lot of benefit for your business.
how would you go about promoting a musician ? i mean i know sites like youtube fb twitter reverbnation and stuff are on the internet but just having an account doesn't get people to see it ? Anyone work in promotions have any tips ? how to get a little feature on a magazines website or blog or something ?