-  Ensuring content is free of typographical, grammatical, spelling, punctuation, syntax, formatting and other such errors.

- Comparing the proofs—printed versions of the manuscript, which include all the formatting, page numbers, headers, etc. that will be included in the final edition—with the edited copy to make sure that no errors have been introduced by the formatting or printing. 

- Things l look for when proofreading;

Spelling and word choice confusions

• Confusions between homophones (e.g. there/they’re/their)
• Misuse of definite and indefinite articles (the/a/an)
• Misuse of prepositions

Misplaced punctuation

• Missing or misused commas
• Confusion between hyphens, em dashes and en dashes
• Incorrect use of apostrophes

Stylistic inconsistency

• Switching between UK and US conventions
• Inconsistent capitalization of terms or titles
• Inconsistent treatment of numbers

Formatting issues

• Incorrect formatting of quotations and citations
• Inconsistent paragraph indentation and spacing
• Missing or misplaced page numbers, headers and footers