1. Don’t capitalize if there’s no reason to.

      It just looks Silly when You capitalize for no Reason.
    2. Every sentence begins with a capital letter.

      You don’t really need an example of that, do you?
    3. Always capitalize the first person singular pronoun, I. 

      "Am I busy?" exclaimed Arthur. "Well, I've just got all these bulldozers and things to lie in front of because they'll knock my house down if I don't, but other than that ... well, no not especially, why?"

    4. Capitalize the first word of every line of a poem.

      Oh frettled gruntbuggly, thy micturations are to me

      As plurdled gabbleblotchits on a lurgid bee.

      Groop I implore thee, my foonting turlingdromes.

      And hooptiously drangle me with crinkly bindlewurdles,

      Or I will rend thee in the gobberwarts with my blurglecruncheon, see 
if I don't!

    5. Capitalize names.

      1. Capitalize names of people, animals, and creatures.

        Mr. Prosser's mouth opened and closed a couple of times while his mind was for a moment filled with inexplicable but terribly attractive visions of Arthur Dent's house being consumed with fire and Arthur himself running screaming from the blazing ruin with at least three hefty spears protruding from his back. Mr. Prosser was often bothered with visions like these and they made him feel very nervous.
        1. Capitalize titles (first and important words) of people, such as Mr., Reverend, Doctor, Senator when used as part of the name.

          And of course, the big news story tonight is the sensational theft of the new Improbability Drive prototype ship by none other than Galactic President Zaphod Beeblebrox.

        2. Capitalize relationships used as names.

          While he drove, Uncle Vernon complained to Aunt Petunia.

          1. Exception: Don’t capitalize relationships when not used as names, and don’t capitalize other words used as names.

            His aunt was back outside the door.

            Yes, dear.

            Later Mom is going to the store.
Later my mom is going to the store.

        3. Capitalize words used as parts of names.

          Alexander the Great

      2. Capitalize names of places and regions.

        The planet beneath them was almost perfectly oblivious of their presence, which was just how they wanted it for the moment. The huge yellow somethings went unnoticed at Goonhilly, they passed over Cape Canaveral without a blip, Woomera and Jodrell Bank looked straight through them — which was a pity because it was exactly the sort of thing they'd been looking for all these years.

      3. Capitalize specific names of things, but not generic types or categories of things.

        Besides the Sub-Etha Sens-O-Matic and the scripts he had an Electronic Thumb.

        Look over there, it’s a tiger!

        Look over there, it’s Tony the Tiger!

        The dog came to school.

        The big, red dog came to school.

        Clifford the Big Red Dog came to school.

      4. Capitalize the names of celestial bodies.

        It takes eight minutes from the star Sol to the place where the Earth used to be, and four years more to arrive at Sol's nearest stellar neighbour, Alpha Proxima.
        1. Exception: Don’t capitalize earth, moon, or sun unless other celestial bodies are mentioned too, or unless it is being used as a name.

          The sun is hot today.

      5. Capitalize the names of books, magazines, songs, poems, articles, chapters, and any other pieces of writing.

        The Hitchhiker's Guide to the Galaxy sells rather better than the Encyclopedia Galactica.

        1. Don’t forget to capitalize the names of your own stories, poems, and plays!

        2. In titles, don’t capitalize articles and prepositions (words such as and, of, or, the, etc.) unless it is the first word.

          1. Remember conjunctions with FANNBOYS: for, and, nor, not, but, or, yet, so.
          2. Articles are the definite article, the, and the indefinite articles, a and an.
          3. Prepositions are words such as at, by, in, of, off, on, up, to.
      6. Capitalize days, months, holidays.

        "This must be Thursday," said Arthur musing to himself, sinking low over his beer, "I never could get the hang of Thursdays."

        1. Exception: Do NOT capitalize seasons.

      7. Capitalize the names of historical events and periods.

        Ford's father was the only man on the entire planet to survive the Great Collapsing Hrung Disaster, by an extraordinary coincidence that he was never able satisfactorily to explain.
      8. Capitalize the names of races, nationalities, languages.

        This suited the Dentrassis fine, because they loved Vogon money, which is one of the hardest currencies in space, but loathed the Vogons themselves. The only sort of Vogon a Dentrassi liked to see was an annoyed Vogon.

      9. Capitalize the names of religions and religious terms.

        Muslims pray to Allah, while Jews pray to God, and Christians to the Christ.
        1. Exception: Do NOT capitalize the word “god” if it is referring to one of many gods in a polytheistic religion.

          Apollo was the god of the sun.
      10. Capitalize company, organization, brand, event, and product names.

        He had never had any money for candy with the Dursleys, and now that he had pockets rattling with gold and silver he was ready to buy as many Mars Bars as he could carry — but the woman didn’t have Mars Bars. What she did have were Bertie Bott’s Every Flavor Beans, Drooble’s Best Blowing Gum, Chocolate Frogs, Pumpkin Pasties, Cauldron Cakes, Licorice Wands, and a number of other strange things Harry had never seen in his life.

        The Nutri-Matic was designed and manufactured by the Sirius Cybernetics Corporation whose complaints department now covers all the major land masses of the first three planets in the Sirius Tau star system.