The seven prepositions that take the dative: mit, nach, aus, zu, von, bei, seit

Seven prepositions ALWAYS put what follows into the dative, with no exceptions and nothing to work out: mit, nach, aus, zu, von, bei, seit. You learn them off by heart, like a shopping list, and from then on the case comes from the preposition and not from the meaning. They also give very common contractions: zu dem = zum, zu der = zur, von dem = vom, bei dem = beim.

The usual slip. Choosing between nach, zu and bei by translation. All three come out the same in your language and are not interchangeable in German: nach for towns and countries with no article, zu for people and for the place you are heading, bei for being at someone's or at a place. nach Berlin, zu Anna, bei Anna, and swapping one for another changes the sentence.

Why it catches you out. English uses «to» for both nach Berlin and zu Anna, and «at» for bei. What helps is that German splits by the kind of place: nach for towns and countries, zu for people and buildings you head for, bei for being at someone's. And seit is not just «since» plus a date: seit zwei Jahren means «for two years».