I must present you with the "GAG" theory... "Gimmicks Are Good!". This theory is one I've developed based on my witnessing of a few successful bands from my "home scene".
Once upon a time there was a band that threw cassettes featuring demo tracks at shows, shot silly string and toilet paper into the audience, played dress up, spanked people on stage, enlisted fire breathers, had an 80 year old ex-comedian perform raunchy comic bantor and (crowd surf), gave out assorted freebies like stuffed animals (often torn to shreds in the mosh pit), stickers, and spark guns featuring the band's logo, and in the beginning played shows for crowds of 10-20. Within a year, attendance to the band's shows grew to hundreds and eventually thousands (at festivals and outdoor venues). This band not only pleased crowds with stage antics but gave them something physical to take with them (besides a bruise from the mosh pit). When an attendee would take a cassette tape, memorabilia, and experiences to share with their friends, the band's following grew. This band is known as Less Than Jake.
In my experience, I've also seen another success story based on this theory... The Know How.
My advice is give some freebies out like copies of demo CDs, stickers, and good old fashioned visceral experiences at shows. This will have a crowd junkified for the crack that is your band's music! If you can get a crowd hooked, they'll buy your CD and merchandise.
By the way, it also helps if you practice, set goals, use the internet, get your friends involved, and know the right people!
One last thing... did I mention the internet?
-Get your band listed on the SKA Toolbar
-Get profiles on sites like Pure Volume
-Get your band's music played on a podcast
This will help you expand beyond the limits of the locale (if that's an issue) and address a broader crowd on an international level.