If you make any changes or improvements to the plugin which you think would be beneficial to others, please consider making a pull request to merge your changes back into the upstream project. (especially if your changes are bug fixes!)
PunishmentsX loosely follows the Google Java Style Guide. Generally, try to copy the style of code found in the class you're editing.
Please make sure to have bug fixes/improvements in seperate pull requests from new features/changing how features work.