Quote Originally Posted by Ramil View Post
As far as I can judge, the tricky part is to know the gender of a noun.
I disagree with this, at least from the perspective of a native English speaker. Unlike, say, German or French, where you just have to memorize the genders of nouns, in Russian you can usually tell the gender just by looking at the word (with exceptions, of course). Obviously you have to learn this before you can understand the declensions, but it's really not difficult.

Memorizing all of the case endings is a bit tough (I remember in school we were all pretty upset by the genitive plural!), but really I think the most difficult part is remembering when to use which case, at least coming from a language with no cases. It just takes a combination of memorization and lots of practice -- I always say I hope to be fluent in Russian on my deathbed