No, except at the beginning of a sentence because it is not a proper noun.
Actually yes. As Champagne is a recognised appellation for wine it is a proper noun for both the region and the wines.
Yes.
Yes, when referring to the title of the President of the United States, it should always be capitalized.
Yes, the word "Tuesday" is always capitalized because it is a specific day of the week.
Yes, the term "Hispanic" should be capitalized when referring to people of Spanish-speaking descent or origin. It is considered a proper noun in this context.
Yes, "I am" is typically capitalized because "I" is a pronoun and should always be capitalized in English.
No, circa does not need to be capitalized.
Yes, it should always be capitalized.
"OK" is typically capitalized because it is an abbreviation of "oll korrect," a humorous misspelling of "all correct." Capitalizing "OK" helps to distinguish it from other words and make it stand out as a separate entity in written text.
No, the word "rif" is not always capitalized. It should only be capitalized if it is part of a proper noun or at the beginning of a sentence.
Yes it should always be capitalized.
Yes, the word "Americans" should be capitalized as it is a proper noun referring to the people of the United States of America.
A common noun is capitalized only when it is the first word in a sentence. A proper noun is always capitalized. An acronym is always capitalized.
Yes, both Hindu and Hinduism should always be capitalized.