I found a book called What the Fach by Philip Shepard while browsing around the internet.
What the Fach is an book with advice about auditioning in Germany, Austria and Switzerland. Lots of subjects are explored in a very up to date way. It was over 30 years ago I did this, and it doesn't look like a lot has changed. This material is only 2 years old. A cursory review tells me that it is not BS.
If you think you would like and might have the goods to have a career in opera singing, this is one path to that goal. I probably violated every recommendation. I was too old, was a contralto, picked the wrong arias, spoke only the smallest amount of German, etc. "Geht dieser Zug nach Grossen Linden?" "Ein Zimmer fuer drei Naechte, bitte." That was it.
These days there are training opportunities all over America. One way to go about it if you are American might be:
1 Find a good voice teacher and take their advice.
2 While you are still young, try to get into the various apprentice programs that exist around the United States. San Francisco, Santa Fe, etc.
3 During steps 1 and 2, study German. Meet people who speak it and practice speaking with them. Get German translations for all your arias and learn these versions.
4 Take the leap and go to Europe. (Notice absence of academia in this list. Janis Martin didn't finish college.)