I came from an academic background, and didn't have anyone else in the team with programming experience when I was researching. I found my time as a contributor for the scikit-learn project to be invaluable in learning about the requirements to build not just working code, but more robust reliable code that others can depend on. Having my work reviewed by those with more experience, making recommendations etc, was fantastic.

So in short, see if you can contribute to a well-run open source project with a good community.