Prepositional case

Learning cases, first of all, you should understand, why do we need it, what function does it fulfill, and only then learn the structures but only with prepositions and situations (like in the situation with the prepositional case - place and object). You should start learning the prepositional case with the analyzing the phrases with the word "где" [gde] (where) - it will help you to understand the logic of case. Try to practise it answering the questions with the interrogative word "где". Then combine the words in the prepositional case with the meaning of place and prepositions В (ВО) (in) and НА (on).

Собака сидит на коврике - A dog is sitting on the rug.
Парень лежит на диване - A boy is lying on the couch.
Политическая ситуация на Ближнем Востоке - The political situation in the Far East.
Моя сестра играет на фортепиано каждый день - My sister plays piano every day.
Мы живем в Екатеринбурге - We live in Yekaterinburg.
Книга лежит в столе - A book is lying on the desk.
Ребёнок гуляет во дворе - A child is walking outside.
Мы с коллегами работаем в офисе - We work in the office with my colleagues.

You can see that prepositional case is first of all connected with the location. The following prepositions, that you need to practise while you are learning the prepositional case, are ОБ (ОБО) (about) - such structures bind a verb to a noun (the questions «о ком», «о чем» - about who? about what?).

Мы любим говорить о музыке - We like talking about music.
Необходимо заботиться о животных - It's necessary to take care of/care about animals.
Журналисты пишут о политической ситуации - Journalists write about a political situation.

Then let's look at the usage of the preposition ПО (meaning «после» (after), «через» (in)). It's rarer occurrence but this preposition also helps you to choose the correct case and word's ending.

По окончании университета - After the graduation from university.
По прошествии пяти лет - In five years.

And, finally, look at the preposition ПРИ (meaning like the preposition В).
Клуб при университете - Club at the university.