One way that anyone can contribute to TeX Live is to email a bug report or enhancement to the tex-live@tug.org mailing list. Please check the known bugs page first, and ideally search the mailing list archives to see if the question has already been answered.
If you're having problems with a particular program or package, as opposed to the general TeX Live distribution, then please send the report to the maintainers of that program. In general, TeX Live just copies whatever is distributed on CTAN.
If you are willing to help test TeX Live, feel free to simply download the current (or test) images and send reports on whatever discrepancies you find. We can always use more testers, on any platform. You'll need a good net connection to download the large images.
If you wish to get your software or package included in TeX Live, please see the advice and requests for contributing packages.
If you would like to contribute new translations or otherwise help with the documentation, please email the doc-specific list, tldoc@tug.org (archive).
If you would like to contribute to TeX Live infrastructure development, including updating packages, installation improvements, building binaries for other platforms, or anything else (especially on Windows), please email. TeX Live uses a subversion source repository.
Anyone is welcome to join the mailing list and participate in the discussion, regardless of their level of involvement. TeX Live is only possible due to the efforts of volunteers worldwide; we welcome all newcomers to the project.
If you like, you can also review this list of general tasks in the TeX community, not specific to TeX Live.
Finally, if you are able to contribute financially, we ask that you join and support your local TeX user group, and/or contribute to the TeX Development Fund.