If you're at a good spot, you can make a few hundred under the table on a busy night. At those places, you don't need to know how to make drinks, they're looking for someone with the right look and personality. Most people don't order anything complicated anyway.
The people I knew at bars just laughed when someone that went to one of those ripoff bartending schools tried to apply for a bartending job. Acting all hard and using a jigger and bragging that they know how to make a godmother or grasshopper or some other bullshyt that no one was ever going to order.
The key is really knowing someone or having a connection with someone that has a good bar. The only jobs that are readily available if you don't know anyone are day shifts at dive bars and those probably aren't even worth taking.