Some Silly Mistakes We've Seen
(our comments are in blue; underlining, bold and italics are added for emphasis)

From the New York Times.
"Most families with children who make about $30,000 or less are also eligible for the earned income credit, which the law does not not change."
Every family should raise a couple of those children. (Both "nots" were there, too.)

"Homes for older adults with all the amenities."
We all want older adults to come with amenities.

So watch where you place "with" clauses. If you don't want to bother, we'll watch for you.

The seriously wrong word--maybe
"There are many underlying factors that play a major role in a child's achievement. Besides the prenatal [(You might mean influences on a developing fetus, but you probably mean parental)], economic, and cultural factors, the family structure can be a major influence."

Wrong word choice
"Over the past several years, XYZ has worked with its affiliates in San Diego and Albuquerque to preserve 385 units and 1,200 units, respectfully. [(respectively)]."

Wordiness
A study was conducted in of three nonprofit acute care hospitals in California, which may have limited application to other settings, . While the article is specifically addressed on the major impetus affecting recent changes in the healthcare system. . .
Take out words that aren't needed.

Inexact word or tone
An early operation and careful patient selection may prevent poor [should increase the likelihood of good] surgical results.