German Grammar Explained /

Dative masculine

Like the accusative, there are recurring letters that will help you get all your dative declensions right. Let's look at a little trick for that.
M R M N
Declensions in dative
Definite
Indefinite/Negation
Possessive
dem
(k)einem
meinem
der
(k)einer
meiner
dem
(k)einem
meinem
den
keinen
meinen
M R M N... looks a bit like MR. MaN!
Haha, true! Maybe that can help you remember :)