Just not be afraid of trying yourself somewhere. You have 4 ways:
- Google Summer of Code
- github/bitbucket, other open repositories where you can participate very easily.
- Huge communities like GNOME, KDE, and etc.
- It is very easy to start your own open-source project and this would very good for your CV.
Opensource called so because everyone can participate.
So, IMO, your first and last problem is your fear.
P.S. It is not dependent on your skill. Anyway, I guess I know what are you seeking for - junior jobs
.
Junior jobs exist almost in each opensource project, but if not - it is easy to explain what it is: junior jobs may be: fixes for minor bugs, typos in the code and other minor changes. After you/project mentor realized that you have enough skills then you/project mentor may ask/give you full repository access to contribute. In other way, you simply can contact project maintainer to ask how you can help to improve this project.
And last - you can simply write documentation for the code, wiki-pages and etc, because each project needs documentation updates or even writing it from scratch.