10 Tips to Balance Parallel Sentence Structure

In crafting sentences that compare one thing to another or represent one thought in contrast to another, writers often omit key words or phrases because they misunderstand how one phrase is balanced against another. In constructing sentences with parallel structure, think of the two parallel elements as figures on a seesaw, and the connecting word or phrase as the fulcrum, then check whether the elements on either side of the fulcrum are equally balanced:

1. "We often pay more attention to them than our own children."
This ambiguous sentence means either that we pay more attention to something than we do to our children, or that we pay more attention to something than our children do. This slight revision reflects that the writer meant the former choice. ("We pay more attention to them" is balanced against "[we pay attention)] to our own children."): "We often pay more attention to them than [we pay] to our own children."

2. "His version is created not with brush and ink, but countless Lego blocks."
The parallel phrases in this sentence, balanced by the fulcrum but, are not "with brush and ink" and "countless Lego blocks," but "brush and ink" and "countless Lego blocks," so repeat with: "His version is created not with brush and ink, but with countless Lego blocks."

3. "The story here is not one of privacy infringement so much as the way real estate is changing because of technology."
The fulcrum in this sentence is "so much as," and the phrase "is not one of privacy infringement" must be balanced against one that starts with the same verb: "The story here is not one of privacy infringement so much as it is the way real estate is changing because of technology."

4. "The rainwater boon isn't so much about taste as reliability in a region where hundreds of wells dried up in the last drought."
This sentence has the same fulcrum as the previous example does, but notice how the sentence reads more smoothly and has more impact because of the inversion of the constituent phrases: "In a region where hundreds of wells dried up in the last drought, the rainwater boon isn't so much about taste as it is about reliability."

5. "They protect consumers from purchasing products that are not effective or even dangerous."
Without the repetition of the phrase "that are," this sentence crashes to a halt with the false parallel terms effective or dangerous. Omit the first word and the fulcrum from the equation, and the resulting sentence, "They protect consumers from purchasing products that are not even dangerous," does not retain the meaning. The point about dangerous products needs a complete phrase: "They protect consumers from purchasing products that are not effective or that are even dangerous."

6. "They believe in cultural and racial diversity, but not diversity of opinions."
Take away the first phrase, and you're left with an omission in "They (don't) believe diversity of opinions," so the preposition in must accompany both phrases: "They believe in cultural and racial diversity, but not in diversity of opinions."

7. "Thanks for your generous assistance and support of these books."
If "and support" is omitted, the phrase "assistance of these books" stands out as faulty, so repair the error with one of these two options: "Thanks for your generous assistance with and support of these books," or "Thanks for your generous assistance and for your support of these books." Better yet, perhaps, is "Thanks for your generous assistance in supporting these books."

8. "Beagles rely on their acute sense of smell to chase their quarry and alert hunters with their high-pitched barks."
Beagles rely on smell to chase their quarry and alert the hunters? No. Their smelling and their barking are two parallel attributes. This sentence requires two independent clauses with parallel subjects: "Beagles rely on their acute sense of smell to chase their quarry, and they alert hunters with their high-pitched barks." (A fulcrum assisted by a "not only . . . but also" phrase might seem useful at first glance, but that revision alters the writer's intent.)

9. "Those who clashed with the color scheme were getting fired or relegated to the stockroom."
Without a balance to either side of or, the sentence implies that people were getting fired to the stockroom or relegated to the stockroom. Repeating the verb clarifies that only the second option involved the stockroom: "Those who clashed with the color scheme were getting fired or were relegated to the stockroom."

10. "Families have been leaving the city not so much because of the form housing takes but its price tag."
The parallel phrases here are (or should be) "because of the form housing takes" and "because of its price tag." Without the following fix to the second phrase, the reader trips into a prose pothole: "Families have been leaving the city not so much because of the form housing takes but because of but its price tag."

Thanks to Mark Nichol / Daily Writing Tips
http://www.dailywritingtips.com/10-tips-to-balance-parallel-sentence-structure/