Replying to Boosting Local scene

The music scene in my city is really lacking. Not lacking in bands, but yet lacking in people that come see the bands.

One of the problems i know is, most of the shows are 19+, and that really cuts down in the amount of people that can come to shows. But still, when there are All Ages show the numbers only increase very slightly.

I want to find a way to help get people more interested in going to shows, but i dont really know how.

How do you guys promote shows in your area and get people wanting to go check out local bands?