om, på or til
This may be a daft one but I'm having difficulty working out which word is most appropriate when translating from English to Danish. They seems to be fairly interchangeble as in, on, for etc.
Don't try to translate prepositions; learn which preposition to use for a given situation.
I agree, it is not very logical.
You might want to skim through book. It has a quite comprehensive section on prepositions: https://nauchidatski.files.wordpress.com/2013/02/danish-an-essential-grammar.pdf