The Descriptive Writer's Full Guide to Punctuation, Grammar, and Sentencing

Capitalization

Capitalize proper nouns and any adjectives formed from them.
e.g.
Washington Monument (a named place)
Dr. Smith, Mrs. Smith, Cynthia, Spots the dog (people's and pets' names)
Mozart-like flair (adjective formed from "Mozart')
Herculean strength (adjective formed from 'Hercules')

Capitalize the pronoun 'I'
e.g.
I am here.
Here am I.

Capitalize the first word of a sentence.
e.g.
Ben jumped over the fence. As he fell, he scraped his knee.

Capitalize names for God and pronouns that refer to Him.
e.g.
The Creator sharpened the chisel He used to shape the world and continued His craft.

Capitalize the first word and all nouns in the salutation of a letter and the first word of the complimentary closing
e.g.
Salutations;
My dear Son,
To my beloved Niece,
To Mr. Cartwright,
Mr. Cartwright,

Closings;
From your dearest son,
From your beloved niece,
Yours sincerely,
Truly yours,

Capitalize only the first word of a direct quotation. Capitalize the first word of the sentence of a direct quotation. Do not capitalize the first word of the second broken part of a direct quotation if the first part ends in a comma, like in example 2. If the first part of a broken direct quotation ends in an exclamation mark or question mark, capitalize the first word of the other broken end, like in example 4
e.g.
"Hermes, you little brat! Come here!" shouted my aunt.
"Hermes," shouted my aunt, "come here, you little brat!"
My aunt shouted, "Hermes, you little brat, come here!"
"Ivanov, that bastard!" spat the illegal weapons dealer, "Hasn't paid in a month." or two unbroken quotations; "Ivanov, that toad?" said the dealer. "Let him in."

Capitalize words of family relationships when used with a person's name or as a substitute for it.
e.g.
This is my uncle, Uncle Trevor.
"Auntie, sit by me."
My niece, Vera, is the worst.
This is Uncle Keith

Capitalize titles and abbreviations of titles that precede personal of official names.
e.g.
Doctor Hae Park, or Dr. Hae Park
Lieutenant Hayes, or Lt. Hayes

Capitalize titles of organizations, literary and music titles, and titles of works of art. Do not capitalize articles (a, an, the), 'and,' 'to,' 'for,' and 'of,' including many other prepositions, unless they are the first word of the title.
e.g.
Librarian Association
Circle of Writers
Ballade No. 8
Waltz of the River
A Tale of Time

Capitalize the first word of every complete line of poetry
e.g.
Polly cannot play today,
She shall come another day.

Because she broke her arm at noon,
she cannot play today.
But Polly will get well so that
she'll come another day.