"I do not like your girlfriend."
Translation:Ich mag deine Freundin nicht.
This tripped me up as well but I'm gonna keep things pretty simple - if there's an object, the "nicht" goes after it. No object, then "nicht" comes after the verb. I'll probably be wrong 10% of the time using that rule but hey! I'll be right 90% which is more than most Austrians :p