The first day someone hires you as a marker start expecting results from the very next day, marketing doesn't work like that. 

I have been there and this is how I make my client understand in the language everyone understands. 

A draw parallel marketing to building muscle basics of which we all have been taught in our school days and most of the time they understand what I am saying.

You can use the same analogy to make them understand how marketing works, hope this podcast helps you a lot