1. Here's one big, red apple. Comma, yes?
2. Two independent clauses (example?) are not the same as two independent sentences, right?
1. Yes.
2. This excerpt has been posted here in AW a few times. I hope you find some of the examples useful. Examples you asked for are listed in item 1:
From "Commas for U.S. Publications"
Noah Webster set forth five easy rules for necessary commas. A very few comma uses are optional. The vast majority of the remainder are superfluous – excessive, pointless, unnecessary.
1. A comma is necessary to separate a compound structure, two or more main clauses joined by one of the seven coordinating conjunctions:
and, or, nor, but, for, yet, so.
The woman drank black coffee, and she ate a croissant.
You can conduct yourself in a pleasant manner, or you can be horrible.
Evan loves Susanne, but he cannot forget Elena.
If the writer chooses to make those constructions into simple sentences, then the comma is not used:
The woman drank black coffee and ate a croissant.
You can conduct yourself in a pleasant manner or be horrible.
Evan loves Susanne but cannot forget Elena.
2. A comma is necessary to separate a long introductory element before a main clause. The rule holds true for both simple and complex constructions.
Even though ignorant of our culture, we must always be kind to strangers. (Simple)
Since Constance is new to our company, all of us should strive to help her. (Complex)
It is always correct to set off any introductory element with a comma, but custom has made the practice optional for shorter elements. Either is acceptable:
Later, you can join us for dessert. Later you can join us for dessert.
3. Commas separate items in a series:
James found blondes attractive, redheads adorable, and brunettes irresistible.
The final comma before the conjunction is
always correct. However, the journalistic practice which came about due to briefer construction (and to save on the cost of lead when linotypes were used) is a viable option:
James found blondes attractive, redheads adorable and brunettes irresistible.
Also correct is:
James found blondes attractive, redheads adorable, brunettes irresistible.
4. Interjections and forms of address are set off with commas.
Yes, I will accompany you to the ball. No, I won’t!
You, sir, are out of line. You may be assured, ma’am, of our concern.
Are you certain of that prognosis, Doctor?
Thank you, Mother, for all you do.
There’s a world of difference in "Let’s eat, Grandma" and "Let’s eat Grandma."
5. Appositives are words, phrases, or clauses of explanation or further identification. They must be set off with commas fore and aft. The rule includes the state following the name of a city and the year following the day of the month.
Mrs. Ellen Bennet, my mother, is in the drawing room.
The Brooklyn Bridge, as opposed to this matchstick construction, is sturdy and reliable.
He was born on June 23, 1941, near Big Timber, Montana, along the Yellowstone River.
5A. The final necessary use of the comma is the most difficult for many writers. It’s actually the same as rule 5, but it’s often presented in isolation because of its difficulty. As with appositives, it separates nonrestrictive clauses in a sentence. The nonrestrictive clause is not essential to the sentence. It merely adds information:
Abraham Lincoln, who was the tallest of U.S. presidents, was an imposing figure of a man.
The grizzly, a bear misunderstood by tourists, is named Ursus horribilis for good reason.
By contrast, a restrictive clause is essential to the sentence:
The lady who cried is my mother.
The man who shot Liberty Valance became a state senator.