For instructions on setting up your environment, refer to Contributing to Oak.
If you have a pull request or want to contribute, reach out to me on twitter (@amirrajan) or via email ar@amirrajan.net (if you want to). We can sit down over a Skype or G+ session and talk through the changes.
I'm not really too concerned with a specific process. So please don't hesitate to send a pull request if you have something you want to contribute. I'll review the changes and touch up anything that needs "polish".