Pratyahara is defined as withdrawal of the senses. At first read it seems like a very austere, cold, monk-like teaching. It seems like it's saying, don't have any fun, don't smell the roses, just sit still and be boring. I don't know about you, but I have an aversion to disciplines that sound in any way forbidding of pleasure. Pleasure is the nector of life!
But upon really exploring this teaching I realized it's actually the most colorful one of all. When put into practice pratyahara unlocks a parallel universe, and "inner reality" which is as vibrant as it can possibly be. The reason is, that although the beginning of the process seems overly sober, what it actually does is uncover truth. The reality is, that all of us are living under some kind of delusion or another which keeps us from experiencing the immense magic our life has the potential to be. 
We get little clues that there's more out there when we step outside our box and explore the world. But those clues also lie within. When we release all stimuli we actually gain access to inner wisdom, and freedom from self imposed constraints based on reactions to our outside world. We emerge with a self confidence and an ability to express ourselves as the unique individuals we are.
The practice of pratyahara is one of moving past the distracting senses of the temporal world, including our own emotions and reactions. Underneath those layers is a universe we can actually have power in because our power is collectively guided for the betterment of all. To consciously hook into this source is the gift those ancient yogi's were passing down to us. This is why I am sitting here today teaching. I am trying to open a door to a reality too beautiful and heavenly to even describe with human words.
I have only seen cracks in the door to it. It opens and closes, I get glimpses, and have moments where I am carried by a wave of great magnitude.  So don't be afraid to get quiet and shut down the noisy outside world. Go inward and explore.