Some art galleries don't even have signs but you can still find them by looking for people talking outside drinking or lots of bikes locked up.
Once inside, get a cheap beer and drink it. This is typically free.
Repeat the last step while attempting to discuss the art. Don't worry if you're not good at this, everyone else is faking it too.
Art shows are a great way to meet people. Most people at art shows are friendly and there is always the art to talk about.