1. The subject of a finite verb is in the nominative and answers the
  question Who? or What?  Sec. 36.

Agreement

  2. A finite verb must always be in the same person and number as its
  subject.  Sec. 28.

  3. A predicate noun agrees in case with the subject of the verb. 
  Sec. 76.

  4. An appositive agrees in case with the noun which it explains. 
  Sec. 81.

  5. Adjectives agree with their nouns in gender, number, and case. 
  Sec. 65.

  6. A predicate adjective completing a complementary infinitive
  agrees in gender, number, and case with the subject of the main verb. 
  Sec. 215.a.

  7. A relative pronoun must agree with its antecedent in gender and
  number; but its case is determined by the way it is used in its own
  clause.  Sec. 224.

Prepositions

  8. A noun governed by a preposition must be in the accusative or
  ablative case.  Sec. 52.

Genitive Case

  9. The word denoting the owner or possessor of something is in the
  genitive and answers the question Whose?  Sec. 38.

  10. The possessive genitive often stands in the predicate,
  especially after the forms of sum\, and is then called the _predicate
  genitive_.  Sec. 409.

  11. Words denoting a part are often used with the genitive of the
  whole, known as the partitive genitive.  Sec. 331.

  12. Numerical descriptions of measure are expressed by the genitive
  with a modifying adjective.  Sec. 443.

Dative Case

  13. The indirect object of a verb is in the dative.  Sec. 45.

  14. The dative of the indirect object is used with the intransitive
  verbs credo\, faveo\, noceo\, pareo\, persuadeo\, resisto\,
  studeo\, and others of like meaning.  Sec. 154.

15. Some verbs compounded with ad\, ante\, con\, de\, in\, inter\, ob\, post\, prae\, pro\, sub\, super\, admit the dative of the indirect object.  Transitive compounds may take both an accusative and a dative.  Sec. 426.

16. The dative is used with adjectives to denote the object toward which the given quality is directed.  Such are, especially, those meaning near, also fit, friendly, pleasing, like, and their opposites.  Sec. 143.

  17. The dative is used to denote the purpose or end for which;
  often with another dative denoting the person or thing affected. 
  Sec. 437.

Accusative Case

  18. The direct object of a transitive verb is in the accusative and
  answers the question Whom? or What?  Sec. 37.