@burcinc-- That's a great analogy! Another way to remember the difference is to look at the first letter. Afferent starts with A which comes before efferent's first letter E in the alphabet. For our brain to respond to something, first a message has to come to it right? So the afferent neuron comes first. It brings the message and then the brain responds with the efferent neurons which come second.
This is how I studied for my exams and it really helped me remember.