Once your fan page goes live, it's up to you to get your page out there. Everyone involved in the project should share the news with their friends immediately (or at least those who would be interested), and you can go looking for fans and fan pages of similar projects -- as long as you're confident your approach won't look like spam.
And don't forget to take advantage of events: Any chance you have to get an RSVP from a fan, take it. The numbers don't really matter, but the connection is important. Even if it's not really a physical event, simply by casting your new album's release or the move to a new office building as an event creates excitement and the option of attending, even if it's just in spirit.
Of course, the Facebook overlords will eventually do a lot of the work here for you, as their algorithms connect you to similar brands in your category: If all of your fans also like another band, Facebook will eventually mention your page to them, and they'll have the option of visiting your page. You can also take this reciprocal idea into your own hands, and approach other bands to mention your page, or your events, on their own.
Offsite, of course, it's important to make sure your Web presence is represented everywhere it can be. If you have a YouTube channel; a Twitter, Google+ or Reader account; a Web site or a portfolio, you'll want to make sure your "like" button or fan page is easily accessible from each of those places. And likewise, providing links to all those networks and sites on your fan page is a great way to integrate all these different streams into a sensible Web presence. Facebook users hit that "like" button like they're collecting Pokemon cards, so they'll remember to check your offerings later. The easier you make it for them, the more likely they'll see and remember you in their news feeds.
Once your page is up and running, maintenance is important. Get some tips on the next page!