Pronoun References

Basic Principle: A pronoun usually refers to something earlier in the text (its antecedent) and must agree in number — singular/plural — with the thing to which it refers.

Which Hunt
If you wish to write naturally, don’t fuss too much about the usage of that versus which. Obsessive correction (what has sarcastically been called a “which hunt”) is best avoided. If your sense of the language is not strong enough to be sure of the right pronoun, use that for the restrictive cases and which for the others and you won’t go wrong.

Exercises
Exercise on That and Which

Gender-Free Legal Writing – Managing The Personal Pronouns by Arthur L. Close, Q.C.. British Columbia Law Institute, 1998
Having a difficult time with her/him and other awkward ways around pronouns? Check out this gender-free style of writing - one that avoids the pronouns entirely. This manual explores a number of techniques that you may use to create documents that are free of gender-specific pronouns. A terrific guide with plenty of examples of text revised to a gender free style.

Resources

Usage & Grammar

Subject-Verb Agreement

Pronoun References

Apostrophes

Commas

Colons & Semi-Colons

Spelling

Common Words that Sound Alike

Capitalization