How to Become A Developer Coming From A Complete Different Field?

Picture this: you work at the oil industry but the crisis has come and there are literally no more jobs in the industry you work. You start searching for the next big thing and you start to fall in love with software development.

Now, you want to become a developer because you've seen the amazing opportunities it can bring to your overall life and career, but... How do you do it?

How do you make the transition into software development from such a different industry?