Here is a great article on potential proofreading pitfalls. Follow the link to read the source:

Proofreading Pitfalls That Trip Up Even Watchful Wordsmiths
FEBRUARY 13, 2018 • MARCIA YUDKIN

In Wellesley, Mass., a man once handed a bank teller a note that read, “Give me your 10s and 20s and no die pack.” Distracted by the misspelling of “die pack” for “dye pack” (a hidden device that stains money red after a robber leaves the bank), the teller did not realize at first that this was an attempted stickup.

After she reread the note, she crumpled it up, exasperated, and told the guy, “I’m not giving you any money. Now get the hell out of here.” And scram he did.

Unfortunately, such fiascos play out every day. Shoppers are taken aback when they spot a typo on a website that seems to them careless or ridiculous. In some instances, it’s not habitual sloppiness or lack of effort leading to the errors. Instead, situations crop up where even meticulous writers or editors find it tough to catch mistakes.

By keeping an eye out for these glitch generators, you can keep website visitors focused on shopping. Here are the seven situations most likely to cause hard-to-catch typos.

7 Proofreading Traps
Updates. Say you want to rerun a seasonal sale announcement that worked well the previous year. Many merchants simply find last year’s message and change the relevant dates. They forget to change the day of the week in the announcement, however, and when they reread it before posting, they overlook the discrepancy. Any time you reuse and update previous copy, check it thoroughly. Make sure you’ve caught every element that needs to be changed. (continue reading…….)