1.Get yourself a thesaurus—or better yet, two of them. These can be tremendously helpful tools when you’re struggling to find right word. A thesaurus is no substitute for a solid vocabulary, but it is still helpful in a pinch.

2.Avoid using same word too frequently. This can make one’s work sound repetitive. Again, a good thesaurus can be helpful in this regard.

3.Keep your sentences fairly short, since longer sentences can sound unwieldy. I’ve found that 17 words or fewer is a good guideline. Do remember that this is just a guideline, though.

4.Even as you keep sentences short, make sure that they flow together well. Sometimes, unskilled writers will simply chop longer sentences up into shorter segments that don’t blend together smoothly. If in doubt, try rephrasing sentences or adding proper connective phrases (e.g. “then,” “so,” “as a result”).

That's what it says in New College Edition of The American Heritage Dictionary of English Language. But it does not begin to tell story of these mistakes - these embarrassing, costly, terrible typos. I know -- from collecting them, and from personal experience.

I have used these examples as warnings during 30 years of teaching at UCLA Extension, showing that typos are bane of a writer's existence - whether you are a reporter, public relations practitioner, or author.

Years ago I came across a typo that I still consider to be funniest and most embarrassing typo in human history, as far as I know. Many considered it terrible. It was probably also one of costliest, if not costliest.

It occurred in London, in 1632, with printing of Baker's edition of Bible, known ever since as "Wicked Bible." The Seventh Commandment, "Thou shalt not commit adultery," suddenly appeared in a revised version, "Thou shalt commit adultery."

I suspect that this made a number of people in England very happy. But their happiness was short-lived. When mistake was discovered, Parliament ordered all obtainable editions destroyed, fined printer 3000 pounds, and forbade all unauthorized printings of Bible henceforth.

This delicious bit of news came to light in an article by Edward G. de Beaumont, about all kinds of typos. It appeared in May/June 1980 issue of Editors Workshop. The author apparently agreed that "Wicked Bible" typo took prize, because he titled his article, "Thou Shalt (not) Commit Adultery."

"Proofread, proofread, proofread, again, and again and again," I harangue my students. "Read your stuff over, two, three times. Better still, get someone else who can spell and punctuate to proof-read what you have written, also."