How does an artist get a show at a gallery?

I’m an artist looking for a way to sell my art for extra money. Does anyone know the proper way to get a show or be part of a show at an art gallery?
Is there any protocol and any does and don’ts? Thanks!

Frame your pictures. Then photograph them and load the photos into the computer and/or make slides. Then call or visit galleries and show them slides, a web page or a cd depending on what THEY tell you to do.

That’s how you do it.