German

A West Germanic language spoken mainly in Germany, Austria, and Switzerland.

Prepositions

‘Durch, für, gegen, ohne, wider, um / kennst du nicht dein Akkusativ, dann bist du wirklich dumm!’
‘Aus, bei, mit, von, nach, seit, zu / kennst du nicht dein Dativ, dann bist du eine Kuh!’
An, auf, hinter, in, neben, über, unter, vor, zwischen take dative for location, accusative for motion
statt, trotz, während, wegen: notionally genitive, aber hier ist der Dativ dem Genitiv sein Tod.
außerhalb, innerhalb: again, notionally genitive, but you can add ’von’ and use the dative colloquially, too.

-e often means ‘feminine’, -er often means ‘masculine’ (except when they mean ‘plural’, but if you don’t know whether you’re talking about one or many, you’ve got other problems)
-chen/-lein is always neuter
-ung is always feminine

If you think of definite articles as being the ‘strongest’ class of articles, no article at all being the ‘weakest’, and indefinite articles being the middle: the declension strength of adjectives is always the inverse of the strength of article. You might think this makes things more confusing, but I find it quite a useful mnemonic.

Verbs whose infinitives begin with ge- (almost?) exclusively take the dative case for their objects.