My interest in programming started in highschool or (Gymnasium) as we say in Sweden, and I did lots of projects, which I don't have today. Then I started university completed about 6 courses in mathematics and 2 programming courses. But I couldn't handle it at that time, and now I don't have the option of completing my education formally.
It's my dream to become a professional programmer or developer, I'm 24 now and I'm totally lost. I know lots of theoretical knowledge, and know C, C++,C#, Java, Python, x86 Intel asm very well. I know how a CPU is built from nand gates, and basics of algorithms and datastructures, but I don't know what to program, so I don't have many completed projects.
I have tried to get into opensource, but I have no idea how to do that in a good way.
To be clear what I'm asking for is advice on what is a good way to become a professional programmer. What do employers seek when they hire? How to get the experience they want when they hire you.
And if you think my question is to broad, just tell me a good project to program to hone my skill, or even better if you can recommend a good way to get started in opensource.