I am trying to translate this sentence: "Service charges are excluded but you only need to pay this if you will eat in restaurants."
Is this an appropriate translation: "Serviceavgifter er ikke inkludert men du må kun betale det om vil du spise i restauranter." ?
Well done! Replace det with either the object pronoun dem (the subject is serviceavgifter - de) or disse (=these), and you have a perfectly valid translation.
In written form I would also add a comma after inkludert, but don't worry too much about that unless you feel ready for some real pickiness.
How about "If you see something, say something"? Is "Om ser du noe, du må se noe." an acceptable translation?