When you are playing your next gig, take a look around the room. Who do you see - fans or friends? Make no mistake about it - they are not the same thing. One potential pitfall of sticking to your local music circuit is that you can pack out a venue with your work friends, school friends, family members, friends of friends and other people in your general social web, which might make for a fun night, but doesn't really add up to much for your music career.
What's the danger? Well, for starters, it can be very tempting to confuse your personal popularity and your musical popularity. You may think that you're "too big" to be an opening act for a tour band, for instance, because you regularly pull in a decent crowd on your own. Why should you make less and play to fewer people?
The thing is, when most of your audience would be just as likely to be in attendance if you were holding a birthday party, bridal shower, wedding, work meeting, etc, etc - then you're really just have a series of house parties in clubs.
While there is absolutely nothing wrong with having a supportive group of friends checking you out every time you play, you must make it a point to take the stage in front of new audiences. Looking out at a sea of unfamiliar faces is a very good thing when you're trying to promote your music. To reach these new audiences, you may have to bite the bullet and take opening slots or smaller shows that you might feel like you are a little beyond. The truth of the matter is that you're never REALLY beyond that. You start from scratch with every single new person who gets to hear your music. That never changes - no matter how many friends you can get to pack out a room.