Thanks for your interest in contributing to Fez.
You can of course fork the project, do your intended changes and create a pull request. But to get the maximum benefit by contributing it would be good to get in contact with us and telling us about your intentions This helps avoiding duplicate work or your changes being refused for some reason.
What is currently missing is a useful website. Anyone with some skills in web design who is willing to contribute to such a website is highly welcome.
Of course Fez has bugs. If you find them please file an Issue so we can resolve them.
Before writing some code you should definitely contact us before writing anything. This allows us to find out whether your contribution can be included in Fez and possibly saves you some fruitless work.
When writing some code please follow our code conventions.
Please structure your commits logically and respect the original formatting. Do not change formattings unrelated to any functional changes, even if the existing formatting violates the styleguide. To do such formatting changes, please prepare a separate pull request.
To contact us, please write an email to fez@poiu.de.