Hi Gentoo team, I would love to contribute, and I think best way is to start with translations. I am a native German speaker, and fluent in English (I could also provide French and Spanish, but I am not that fluent in those, so I would rather wait some more years before requesting that ;) ).
I noticed you already have a bunch of German translators, still there are a lot of pages untranslated (e.g. the official Handbook (AMD64 variant) which has only a few sentences/paragraphs translated), so I guess there's still a lot of work to share. :)