For definitions of the various kinds of pronouns and their roles in a sentence, click HERE.
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.
The indefinite pronouns anyone, anybody, everyone, everybody, someone, somebody, no one, and nobody are always singular. This is sometimes perplexing to writers who feel that everyone and everybody (especially) are referring to more than one person. The same is true of either and neither, which are always singular even though they seem to be referring to two things.
The need for pronoun-antecedent agreement can create gender problems. If one were to write, for instance, "A student must see his counselor before the end of the semester," when there are female students about, nothing but grief will follow. One can pluralize, in this situation, to avoid the problem:
Too many his's and her's eventually become annoying, however, and the reader becomes more aware of the writer trying to be conscious of good form than he or she is of the matter at hand.
Trying to conform to the above rule (#2) can lead to a great deal of nonsense. It is widely regarded as being correct (or correct enough), at the beginning of the twenty-first century, to say
but many people would object its being written that way because somebody is singular and their is plural. There is a great deal to be said, however, for using the word their as the gender-non-specific, singular pronoun. In fact, it's been said already, and you can read all about it at the The University of Texas, where a web-site has been dedicated to the use of their in this way in the writings of Jane Austen, William Shakespeare, and other literary greats. At least it's nice to know you're not alone! Another site dedicated to the "gender-free pronoun" is at Gender-Neutral Pronoun Frequently Asked Questions.
Remember that when we compound a pronoun with something else, we don't want to change its form. Following this rule carefully often creates something that "doesn't sound good." You would write, "This money is for me," so when someone else becomes involved, don't write, "This money is for Fred and I." Try these:
Those are both good sentences.
One of the most frequently asked questions about grammar is about choosing between the various forms of the pronoun who: who, whose, whom, whoever, whomever. The number (singular or plural) of the pronoun (and its accompanying verbs) is determined by what the pronoun refers to; it can refer to a singular person or a group of people:
It might be useful to compare the forms of who to the forms of the pronouns he and they. Their forms are similar:
To choose correctly among the forms of who, re-phrase the sentence so you choose between he and him. If you want him, write whom; if you want he, write who.
The only problem most writers have with whose is confusing it with who's, which looks like a possessive but is really the contraction for who is. In the same way that we should not confuse his with he's (the contraction for he is or he has), we should not confuse whose with who's.
Whose can be used to refer to inanimate objects as well as to people (although there is a kind of folk belief that it should refer only to humans and other mammals): "I remember reading a book whose title I can't recall right now about a boy and a basenji."
For additional help recognizing and working pronouns, see Chapter 13 of Sentence Sense: A Writer's Guide.