Hi, Samantha --

Thanks for considering me as your editor. The most common mistakes I find in non-fiction writing fall into three categories.

(1) Sentence structure. Some writers try to convey complex, connected ideas in a single sentence. With careful construction, this can be accomplished, but it's often better to break the information down into smaller pieces and then connect them with a summary statement. This is more important when writing for the mass market than in academia, but I believe clear, concise writing is almost always preferable to convoluted writing.

(2) Usage. Frequently people will use a word they've read elsewhere without fully understanding what it means, for example putting "nonplussed" (which means confused) when they mean "not bothered." Or they'll insert a malaprop by using a word that sounds like the one they need, e.g., respectively instead of respectfully.

(3) Punctuation. Errors with commas and hyphens are most common. Many people also misuse dashes, or omit them when they might be useful.

Good luck with your studies at U Penn. -- Kristen