In the state of today's music world the biggest place to promote is online of course. Facebook is the hottest thing, second is Twitter, third is your own website, fourth is Reverbnation.com, and fifth is a free Craigslist music listing.
There are seriously dozens of resources for every local band that don't always get utilized.
With everything being so digital most bands have lost the love for fliers or gig posters. Each show should have a flier, if you're disregarding this as old school you're losing out on a powerful way to gain fans.
Don't you (directed towards everyone over 21) remember the first time you saw a flier in a music shop, coffee shop, or tattoo parlor with your favorite band on it and thinking "WOW, I'm gonna snag this and keep it forever!"
Most of us have a stash of those type of fliers along with ticket stubs.
How the hell do you gain fans with fliers??
Each flier needs to be looked at as a piece of art. A PIECE OF F-ING ART!
Not a piece of paper with band names listed in different fonts but an awesome, eye catching art piece that someone will hold on to for months after the show or some new music fan will look at and think "WOW, this is sweet! I wanna go check these bands out!"
Example of a BAD flier that won't get anyone's attention:
If you doubt the value of gig poster art check out this amazing site I've been a member of for years.
You can always find artists, graphic artists (like myself)or friends who are just handy at cutting and pasting stuff together to make amazing fliers within your music scene. Most musicians are artistic in other ways beyond instruments. Utilize these resources.
Once you have a kick-ass flier print out enough to spread all over your town, hand out at other shows, and keep on hand at your show for people to grab as a keepsake or something. If you're not willing to do more than send out a facebook invite you're shooting yourself in the foot.
As seen on gigposters.com even HUGE bands who have sold out crowds have artists create gig posters for their shows.
So GET ON IT! Make fliers, hand them out and post them up!