1. When the subject of a sentence is composed of two or more nouns or pronouns connected by and, use a plural verb.
2. When two or more singular nouns or pronouns are connected by or or nor, use a singular verb.
3. When a compound subject contains both a singular and a plural noun or pronoun joined by or or nor, the verb should agree with the part of the subject that is nearer the verb.
4. Doesn't is a contraction of does not and should be used only with a singular subject. Don't is a contraction of do not and should be used only with a plural subject.
5. Do not be mislead by a phrase that comes between the subject and the verb. The verb agrees with the subject, not with a noun or pronoun in the phrase.
6. Expressions such as with, together with, including, accompanied by, in addition to, or as well as do not change the number of the subject. If the subject is singular, the verb is too.
7. The words each, each one, either, neither, everyone, everybody, anybody, and nobody are singular and require a singular verb.
8. Nouns such as civics, mathematics, measles, and news require singular verbs.
9. Nouns such as scissors, tweezers, trousers, and shears require plural verbs. (There are two parts to these things.)
10. Sentences beginning with there are are usually in inverted order. Be sure the verb agrees with the subject. There is never a subject of the sentence in the true sense of the word.
11. A collective noun requires a singular verb if the group is thought of as a unit (The family holds an annual reunion). In a very few cases, the plural is used if the individuals in the group are thought of and specifically referred to (My family have never been able to agree).