The rules for capitalization in German and English are vastly different. Here are some quick tips.
1) Unlike in German, the vast majority of nouns in English are NOT capitalized.
2) Any word involving a nationality, ethnicity, or religion is capitalized, whether it is an adjective or a noun.
I like German beer.
That is the Bavarian flag.
I’ve never dated an American.
He is Austrian.
3) The word “I” is always capitalized (unlike “ich”). Also, the word “you” is only capitalized when it is at the beginning of a sentence (unlike “Sie”).
There are more rules than this, but these are three that differ vastly from German.
For all more comprehensive list of capitalization rules, visit this webpage: