Hi, Tihana. Wow, what an interesting question!
Five years ago, I brought a book for beginners (covering up to level B2) in which the seven cases are gradually introduced alongside usage examples in what the book considers as "practical" situations.
However, knowing theory is one thing, it's quite another to put it into practice. I try to watch, listen, or read something every day, in the hopes of approximating the exposure level that a native would have. This is the greatest contributor to learning those cases, in my opinion.
I also have a few language partners from the Balkans, as well as an italki profesor. Unfortunately, speaking remains my weakest area, as I don't practice it nearly as frequently as I do the other skills.
What are your methods for teaching padeže?