Getting people to come out to your shows is the name of the game, but who you bring is just as important as how many you bring. Fan growth has to be sustainable for you to have a future in music.
Lately I've seen some local bands that miss the "sustainable" aspect of this formula. The band just printed off a new set of t-shirts (that look quite fantastic!) to help cover costs and plan for their next album. Cool, so I helped them out and bought one.
As we talked, however, I started to realize that the only people they were selling t-shirts to were other bands, not approaching new fans at shows.
It's not that it's bad to give and receive support from other bands, it's quite important actually. But this isn't sustainable fan growth. Musicians, (surprise!) have limited time and cash. There's a limit to how much each person can give.
Selling one shirt to another band will make you a couple bucks. Selling one shirt to an honest fan will make you a couple bucks now, plus increased devotion to your band. The real value in selling merch is helping your fans express their fandom to others. (Remember my post on fan identity?)
You've only got so much time and energy to sell, make sure you focus your efforts on the long-term. Are you selling to the right people?