Resolved questions
How to make diminutive nouns in Russian language? Oh God! The Russian language is too complex! :)

I've read the http://en.wikipedia.org/wiki/Diminutive page. And you know what? I have no idea what those diminutive nouns in russian. I suggest you to stop concentrate on the grammar and start listening to simple russian. If you want ever to master a language you should listen to simple language for thousands of hours.

Hi! I think, you shoud take a noun and add the suffix. For exsample: mouse(мышь)+suffix(онк)= мышОНОК. This is called for Russian "уменьшительно-ласкательное существительное"

There are very many specific cases for various categories of nouns. I don't think you need all these rules if you are not at an advanced level yet. I have a feeling that there are almost as many rules as there are nouns and adjectives. If you come across such nouns in your texts just remember individual cases for the time being. I would not advise you to try constructing diminuitive nouns yourself as the chance that it will sound wrong is very big. Moreover you have to take into account the subtelties of the situation when you can use them and when it will sound inappropirate. Sorry, it seems like that.

Good news: men use such words more rare than women.