Start by reading here Creating packages - ArchWiki
You could then help ( if you find problem ) by improving the PKGBUILDS Groups · Packages · GitLab If you really see a problem.
But also you could help by creating new PKGBUILDS and releasing them on AUR, ( that helps all Arch based distros ).
For example, you use some niche software that has only github page where the creator of the software gives only compilation steps. You can create a recipe PKGBUILD that handles that compilation and release on https://aur.archlinux.org/