One of the best ways you can contribute is to simply use the API and share your bug reports and enhancement suggestions on Github. These can cover anything: from APIs that don’t work properly through to needed features or documentation.
If you want to take a more active role, then a good place to start is with the project’s open issues on Github. In particular, documentation issues can be resolved without a deep knowledge of the code, and will help you learn more about the project.
If there is a feature that you want to add, then please do so! Before you start we highly recommend that you first create an issue in Github so it can be tracked and discussed!