The words that should start with a capital letter are places, names, important words in a title, and the letter at the start of a sentence.
No Only names of people or places etc have capital letter at start
Yes, all books start with a capital letter.
Yes it should.
No it won't, unless it is at the start of a sentence.
It should start with a capital letter at the beginning of a sentence because it is n ot a proper n ou n.
Yes, "Best wishes" at the end of a letter should start with a capital letter.
Yes - all planets names begin with a capital letter.
no. its not a place, it not a person, and it should not be a capital letter.
not if it doesn't start a sentence.
No, there should not be a capital letter after an exclamation mark. After an exclamation mark, you should start the next sentence with a lowercase letter unless it is a proper noun.
Colors do not need a capital letter unless it is part of a Title. e.g. The Red Badge of Courage (a book)
Madrid is the capital of Spain. The company needed to raise more capital in order to expand. A sentence should start with a capital letter.