The best way to contribute to the Apache foundation is to get involved with one of its many communities.
Use the products and give us feedback
Using the products, asking (and later answering) questions, reporting bugs and making feature requests are critical parts of the project community. User feedback can strongly drive the projects and the technologies.
Contribute back to the community
Beyond the user activities, it'd be great to see you helping with the development of the projects. This can mean getting involved with the discussions on the development mailing lists, answering user questions, providing patches for bugfixes or features, and helping to improve the documentation.