I think a good thing is for all American English speakers to try to at least for a little go to chat to someone from Manchester England or go there in person for a while.  Why?  It can come in handy for German pronunciations of vowels.  Northern English is the closest vowel relationship to German.  If you first learn Mancunian English, then you can apply Mancunian vowel pronunciations to German words if you do not know a particular German word and it will be the closest guess.