As a native speaker you normally don't have to care much about any rules concerning the gender of a noun, as you learn it automatically when you grow up. That means - even without knowing any rules (like e.g. those on this website: http://deutsch.lingo4u.de/grammatik/nomen/genus
) - you always apply the correct gender without thinking about it (at least from a certain age). But, of course, there are other rules where lots of native speakers still make errors (I think it's the same in all languages).
One phenomenon of our time is, that the genitive is often replaced by the dative. I 've got the impression, that less and less are applying the first one.
As a foreign language learner, I can surely understand your problem. Even in languages with only 2 different genders, I can't always remember which one is the correct. When I started to learn Russian about 10 years ago, I was even overwhelmed by all the different endings (5 different cases for every noun) of the same word and so I stopped my studies 2 weeks later. But maybe - one day - I'll dare to give it a retry.
When I learn a new noun in another language, I always compare the gender with the German one. If it is the same it's fairly easy, if it is a different, I sometimes try to find a word in my language which has a relation to the other and which has the same gender as the foreign word.
Example: das Buch (n.) in French: le livre (m)
One German word which has a relation to "das Buch" but the same gender as in "le livre" in French is "der Buchstabe" (m) (relation: in almost every book you can find letters).
It's easier for the brain to learn words or numbers if you have a connection to other things, events, memories etc.