What are the Grammatical Rules for Capitalization of Text?

To write a sentence appropriately, we must know the key rules of capitalization. Here some rules are mentioned precisely.
•    The first word of each sentence should be a capital letter.
Example: Start a day as early as possible.

•    Proper nouns always start with the capital letter.
Examples:
I have got a nice gift from Uncle George. (Here, uncle starts with a capital letter ‘u’ as the name is also mentioned in the sentence.)
My uncle stays in Mumbai. (Here, ‘U’ is a small letter, as it is used generally.)
More Examples:
She likes the poems of Rabindranath Tagore. (The name should start with a capital letter)
I like John’s efforts towards the literacy campaign.

Key Rules, Along with the Examples:

The names of hills and mountain ranges always start with a capital letter.
            Example: Mt. Vesuvius, Mount Everest

The names of the oceans, rivers, lakes, seas should start with a capital letter.
            Example: the Indian Ocean, the Ganga, etc.

The building’s names should be written by starting with a capital letter.
            Example: the Eiffel Tower, the Writers’ Building

The names of schools, colleges and universities start with a capital letter.
            Example: the Harvard University, the Calcutta University.

Streets names are also written by capitalizing the first letter.
Example: the Park Street.

The titles of movies, magazines, books and songs should start with a capital letter.
            Example: The Washington Post, One Indian Girl, Times of India, etc.

The names of regions, continents, states, countries, cities and towns always start with a capital letter.
            Example: London, South America, Chennai, etc.

The periods and events are always commence with a capital letter.
Example: Age of Enlightenment.

The trademarks start with the capital letter.
            Example: Samsung, Sony, Toyota

The pronoun ‘I’ is always a capital letter.
Example: I love to read different story books as well as articles. (Correct)

I want to go for a long vacation. (Incorrect as here ‘i’ is not written with a capital letter.)