Unless you are very lucky indeed, you spend a large amount of your time as a professional musician finding work for yourself. Organising rehearsals, finding gigs, getting people to support you by purchasing tickets, albums and merch.
One of the best ways to grow your audience, and sell more tickets, is to create and maintain an effective online presence. Get your WordPress, Facebook, Twitter, Google+ and LinkedIn working for you. Announce your tours, gigs, post press, reviews, special offers, newsletters. All this can very easily get on top of you though, but I think I may have found the most useful tool in the Artist PR Machine: CoSchedule.com