Nouns: Case: Dative

Dative case denotes (primarily) the indirect object, that is, the recipient or beneficiary of an action.  It answers the questions: кому? чему?  to whom? to what?

Major uses of the dative:

 1. The person being spoken to, the recipient of the speech (for most verbs of speaking. Exception: verbs of asking, which may be thought of as "I asked a question of John").

• Бабушка читала нам сказки = Grandma used to read us fairy tales.
• Что говорил вам преподаватель? = What did the teacher tell you?

2. The recipient of things sent or given, such as letters

• Я хочу купить Тане книгу = I want to buy Tanya a book.
• Я пишу письмо другу = I am writing my friend a letter.
• Она купила подарок сестре = She bought her sister a present.
• Иван даёт цветы Анне = Ivan gives flowers to Anna.

3. With verbs that show something being given or transmitted, including assistance

• Я помогаю Анне = I am helping Anna

3. With various intransitive (reflexive) verbs in -ся, where the accusative cannot be used

• Кате нравится русская музыка = Katya likes Russian music. (Russian music pleases Katya)
• Мне нравится твоё платье = I like your dress.

4. With various modals and other constructions in which the "logical subject" is conceived of as the recipient of outside forces, or as the experiencer of outside conditions

• Нам холодно = We are cold (to us it's cold)
• Мне скучно = I am bored (to me it's boring)
• Джону трудно говорить по-русски, а Тане легко = It's hard for John to speak Russian, but easy for Tanya.
• Маме надо готовить ужин = Mom has to cook dinner.
• Студентам нужно заниматься = Students have to study.

5. To express age ("years to someone/something")

• Мне восемнадцать лет - I am 18 years old (to me there are 18 years) 
• Ивану двадцать три года - Ivan is 23 years old.

6. With a few prepositions, mainly К, which expresses movement towards something, and the very versatile ПО, which has several meanings, including a) movement along, b) simulataneous movement, c) distribution, and d) cause.

• Мы идём к Ивану = We are going to Ivan's.
• Такси подъехало к дому = The taxi pulled up to the house.
• Самолёт летит по небу = A plane is flying across the sky.
• Корабль плывёт по морю = The ship is sailing on the sea.
• Мы встречаемся по средам = We meet Wednesdays.
• Папа дал детям по яблоку = Dad gave the kids an apple apiece.
• Он специалист по металлу = He is a metal specialist.
• Фильм снят по рассказу Чехова = The film is based on a story by Chekhov.
• Заяц съел орех по ошибке = The rabbit ate a nut by mistake.
• Она пропустила лекцию по болезни = She missed class because of illness.

7. There are also some compound or participial prepositions which take dative,благодаря, согласно, вопреки), and навстречу. Note: with these pseudo prepositions, the third-person pronouns do not get their leading В.

• благодаря им = thanks to them
• согласно ему = according to him/it
• вопреки ей = despite it/her

Forming the dative case is straightforward.

Masculine nouns ending in a hard consonant have the ending У. Those ending in a soft consonant (Ь or Й) have the same ending, but it's written Ю (and the Ь or Й is removed: remember - ЬУ and ЙУ are written Ю).

Neuter nouns have the same endings as masculine ones. Hard (ending in O) take У, and soft (ending in E) take Ю.

Feminine nouns have the same endings as they do in Prepositional. So, those ending in A have Е, and those ending in soft signs, or ИЯ, take И and ИИ, as their ending.

 Plural is dead easy. Look at the nominative plural. Anything hard (А Ы) takes AM; anything soft (Я И) takes ЯМ.

Singular:
Иван - Ивану
Игорь - Игорю
музей - музею
кресло - креслу
море - морю
здание - зданию
сестра - сестре
песня - песне
история - истории

 Plural
Иваны - Иванам
Игори - Игорям
музеи - музеям
кресла - креслам
здания - зданиям
моря - морям
сёстры - сестрам
песня - песням
история - историям

Here is a link to examples of Russian prepositions taking the dative