Find a person who has a problem. Solve it using code. Now that person will call you a programmer. A useful special case of this: Find someone with some buggy c

Find a person who has a problem. Solve it using code. Now that person will call you a programmer. A useful special case of this: Find someone with some buggy code, fix it for them, and convince them to accept and install the fix. Now you've demonstrated the ability to read code, understand it, debug it, and write a fix that works and that doesn't make the code's maintainer blanch in horror. You're a programmer. When you can, publish your code with an open-source license so that people can read it and borrow it.