Need help in Contributing

I am very much interested in developing application and also interested in Open source softwares and i always promote that. I would like to contribute here and i dont know how to start. I am good in C++, Java, .Net, Web Designing etc. But not an Expert. Kindly help me to start ...

Find a project that is working on a type of software that interests you. Check out their issue/bug tracker and submit patches for anything you're able to fix. If they like you're work they may invite you to be a developer to the project, giving you write access to the repository, influence and other perks.