Thank you for wanting to help out in making Pippel a better open-source software. There are many ways you can contribute to this project, all of which will be greatly appreciated.
The first and foremost way to contribute to this project is to report any issues or failures of Pippel in your systems. I only have access to so many different environments and cannot say with absolute certainty that Pippel is fault-proof. Report such issues as an issue and share as much information that can help in troubleshooting it.
The second way to contribute to this project is to share ideas on what other features you would like to see Pippel implement. I am only a single maintainer, and only have so many ideas. Whether the feature is relevant to Pippel or not is a separate issue, just share it with us and maybe something may come out of it!
Third, being the only maintainer of this (small) project, I am also the only one who will be attending to all issues and feature requests so any help is always welcome, especially when it comes to coding. If there are issues or feature requests that you feel you want to contribute to, please feel free to submit a pull request and see it shared with all the other Emacs users in the world through MELPA!