Ok so I realize that in that first post, I may have rambled on a bit - just trying to explain everything, trying to show the (possibly broken) logic that I see behind it. So, while I'll keep that post up - maybe some of you found it helpful, I've decided to post this - more 'scientific' take on the род. пад. singular. The result, if you ask me, is the same - this way there's just more memorization.

1) Masculine
-----------
Ending|/|-й|-ь
:---:|:---:|:---:|:---:
Add|-а|-я|-я

2) Feminine
--------------
Ending|-а|-я|-ия|-ь
:---:|:---:|:---:|:---:|:---:
Add|-ы|-и|-ии|-и


3) Neutral
--------------
Ending|-о|-е|-ие|-я
:---:|:---:|:---:|:---:|:---:
Add|-а|-я|-ия|-ени

Examples:

Masc.
----------
1. Челове&amp;#769;к -&gt; Челове&amp;#769;ка
2. Музе&amp;#769;й -&gt; Музе&amp;#769;я
3. День -&gt; Дня

Fem.
------
1. Сторона&amp;#769; -&gt; Стороны&amp;#769;
2. Земля&amp;#769; -&gt; Земли&amp;#769;
3. Фами&amp;#769;лия -&gt; Фами&amp;#769;лии
4. Дверь -&gt; Две&amp;#769;ри

Neut.
-------
1. Нача&amp;#769;ло -&gt; Нача&amp;#769;ла
2. Пла&amp;#769;тье -&gt; Пла&amp;#769;тья
3. Мне&amp;#769;ние -&gt; Мне&amp;#769;ния
4. И&amp;#769;мя -&gt; И&amp;#769;мени

Родительный Падеж Singular

Masc.

Fem.

Neut.