What is the difference between the Oxford, Harvard, and the Serial comma?

The Oxford comma (also known as Harvard comma or Serial comma) is the comma inserted just before the coordinating conjunction (usually ‘and’ or ‘or’, and sometimes ‘nor’) in the last item of a list of three or more items. For example: Gurpreet's blog is dedicated to Jack, Jill, Red Riding Hood, Captain Kirk, and Spock.

When to use the Oxford Comma?

I use a serial comma ONLY when it satisfies all the following three conditions:

Use everyday (one word) only when adjectival, as an everyday occurrence, our everyday life.

In all other cases, use two words: ‘He comes here every day.’ ‘Every day somebody dies.’

It's amazing how a little word that looks innocuous changes the entire meaning of a sentence.

Keep this difference in mind, and stop making this simple error an everyday occurrence.

The difference between a customer and a client can at first seem quite confusing. Some people say there is not much difference, while others say it depends on the industry as to whether the term customer or the term client is used for business patrons. The difference between a customer and a client can best be seen in terms of an ongoing business.

A client looks to follow the advice and professional knowledge of a business leader, while a customer may only purchase goods and services from a business

Simply put:

“Never split an infinitive”. This sixth-grade commandment is almost a myth.

To split or not to split? The debate continues between traditionalists and the modernists; yet, writers have been splitting infinitives for hundred of years. Even Shakespeare has done it.

Fowler, Strunk and White, and a long list of others advise us to avoid splitting if we can. They do, however, say that splitting is acceptable if it results in improved clarity.

1.A device, or shortcut, that damages a sentence and often leads to confusion or ambiguity.
--Strunk and White, The Elements of Style

2.This hybrid term has been referred to as “that befuddling, nameless thing, that Janus-faced monstrosity, neither word nor phrase, the child of a brain of someone too lazy or too dull to express his precise meaning, or too dull to know what he did mean.”
--Bryan A Garner, A Dictionary of Modern Legal Usage

The Oxford Dictionary of American Usage and Style says:
"As conjunctions, the words are virtually interchangeable. The only distinction is that 'although' is more formal and dignified, 'though'
more usual in speech and familiar writing. In certain formal contexts,however,'though' reads better."

Although is felt to be stronger than though and is therefore more frequently used at the beginning of a sentence, and internally when emphasis is desired. ‘He insisted on doing it, although I warned him not to’.

Dates usually contain parenthetic words or figures. Punctuate as follows:

April 6, 1956
Wednesday, November 13, 1929

Note that it is permissible to omit the comma in

6 April 1956

The last form is an excellent way to write a date, the figures are separated by a word and are, for that reason, quickly grasped.

--William Strunk, Jr., E. B. White, The Elements of Style, 2d ed.p3

One may unimpeachably write either May 26, 1984 or 26 May 1984. The latter—the primarily BrE method—is often better in prose, for it takes no commas.

What's an ampersand?
The ampersand (&) is a symbolic abbreviation for the word 'and'. Historically, & was the 27th letter of the alphabet. The name comes from the words 'and, per se and'. The symbol is a stylised version of the French word 'et' (meaning 'and').

When is it proper to substitute an ampersand (&) for the word and? Dan Santow of Word Wise provides these rules:

[T]hough an ampersand is the symbol form of the word “and,” it is not a substitute for the written-out word except in these very specific cases:

Per is Latin. Per day; per month; per year; per hour are mongrels of Latin and English. They are inferior to ‘a day’ (twenty rupees a day), ‘a month’ (three thousand a month), ‘a year’ (one lakh a year), ‘an hour’ (fifty miles an hour).

Generally, it is well to confine per to its own language: per cent, per capita, per annum, per contra. A hundred pounds a year is more natural than a hundred pounds per annum.

Anticipate and expect are thought by some people to be interchangeable, but that takes away a useful distinction.
Anticipate: The primary meaning of this is to foresee an event and to take some action to prepare for it or to prevent it: He had anticipated the question, and had his answer ready
So anticipate means foresee and prepare, not merely expect.
If I am playing chess and I anticipate my opponent’s next move, I see it coming and act accordingly. There is action as well as expectation.