Setting off in commas states (after cities) and years (after dates)

Not sure why, but many college students have trouble setting off states (after cities) and years (after dates) in commas , as in -- Boston, Massachusetts, is the cradle of liberty. And, Tracy applied for the job on April 13, 1993, and accepted it on Monday, May 24, 1993.

This falls in a note under the sacred of Harbrace section 12d, which states:

Commas set off nonrestrictive and other parenthetical elements as well as constrasted elements, items in dates, and so on.

Nonrestrictive clauses or phrases give nonessential information about a noun or pronoun. They can be omitted without changing the meaning. Restrictive clauses or phrases are essential to the clear identification of the word or words they refer to. They limit (rather than describe) those words by making them refer to a specific thing or person or to a particular group.

Subnote:
Geographical Names, Items in Dates and Addresses
This subnote contains the examples above. Note that commas are omitted when the day of the month is not given or when the day of the month precedes rather than follows the month (European style), as in -- Tracy applied for the job in April 1993 and accepted in on Monday, 24 May 1993.

Pulitzer Prize-winner Kathleen Parker thanks her 11th-grade English teacher

A sprig of verbena and the gifts of a great teacher
By Kathleen Parker
In 11th grade, my life changed in a flicker of light


Mr. James Gasque enters the Grammar Tip of the Day pantheon.
Bring back diagramming sentences!

From Ann Wylie's Writing Tips

Ann Wylie is a great writing teacher, and her Wylie's Writing Tips e-newsletters are filled with useful, practical ideas. (Click here to subscribe.)

Here are three tips from her April issue:

After a couple of months of reading on a reader, I decided to review my clippings. What I found will help me — and, I hope, you — model the masters, or steal techniques from some of the year's best writers to make your own writing more creative and compelling.

1. Use metaphor, not modifiers.
One problem with modifiers — thin, lean, straight — is that they don't paint pictures in your readers' heads. Instead of simply describing your subject with adjectives and adverbs, engage your readers' senses with analogy.
Meg Gardiner used this technique to describe a charismatic religious leader in her Edgar Award-winning mystery, China Lake:
"Peter Wyoming didn’t shake hands with people; he hit them with his presence like a rock fired from a sling-shot. He was a human nail, lean and straight with brush-cut hair, and when I first saw him he was carrying a picket sign and enough rage to scorch the ground."
Find yourself writing an adjective or adverb? Could you develop an analogy instead?

2. Coin a word.
Rebecca Goldstein is quite the neologist. In 36 Arguments for the Existence of God, she creates half-and-half words in this passage:
"Auerbach harbors such impatience for the glib literati—the 'gliberati,' as one of his own digerati had christened them—that Cass has wondered whether there might not be some personal history."
Can't find just the right word? Why not make one up?

3. Twist a phrase.
To call attention to an idea, change a word or two in a colloquialism to give it new meaning.
After seeing David Mamet's Boston Marriage hilariously performed by the Kansas City Actors Theatre, I read the play to make sure I didn't miss any lines like this phrase twister:
"ANNA: Have you taken a vow of arrogance?"
Want to call readers' attention to your point? Surprise and delight your readers with twist of phrase.