You have to take this up a notch, or else we'll all be cannibalizing each other. Hair salons don't stay in business giving haircuts to other hairdressers. Plumbers don't make a bulk of their business from other plumbers. Restaurants usually don't promote their place to other chefs.
As musicians, we can help our fellow musicians in a way that fans can't. When a musician helps a fellow musician, they are sacrificing time and energy they can put towards their passions and goals. Because of that, just going to each other's shows isn't enough.
If someone comes to one of your shows, invite them on stage to perform a few tunes to give them exposure and hype their next show. Introduce that person to your fans, as well as the club manager, promoter, booking agent, etc. Don't treat your fellow musician like another ticket sold or a competitor, but an ally to improve the scene.
"Look everyone, there's Derek from the Dominoes. Hey, Derek, why don't you come up to play one of your awesome tunes!"
"Thanks, Eric, it's an awesome pleasure to get to sit in with a talented band like this. Don't you think folks?"
The crowd cheers, and the band jams one of Derek's tunes, and the crowd is cheering again.
"Thanks for sitting in with us Derek. If you want to see more of Derek, make sure you visit derekandthedominoes.com to see where he's going to play next."
Later on.....
"Hey, Mr Seedy bar owner, I'd like you to meet Derek"
"Hi Derek, I really liked that tune, how about you play here one of these nights"
"Sure, Mr Seedy, how about we have Eric's band share the bill?"
"Sounds good, let me get out my calendar....."
IMO, to really help a scene, we need to replace competition with collaboration, turf protection with sharing, and cliques with community. To do this, we need to check our egos at the door and realize we're all in this together. "We shall all hang together, or together we shall hang"