Cleanliness

"Learn to withdraw the mind from the physical senses:

freed from its ties the outer objects, the mind can arrive at its own real nature"

Sutra 2.54

Pratyahara mean to withdraw the senses…but what does that mean?
On a very basic level to withdraw the senses means to move inwards, to look for on outer support on which to focus your concentration on, and from that begin the journey in. Letting everything around that one point of focus, fall away so that your senses are not distracted and you begin to feel what is happening inside. I was reading How Yoga Works by Geshe Michael Roach and Christie McNally and I stumbled on to this story:
"Here's something to think about when we're talking about focus, and how it affects your channels and inner winds. Normally, when someone tells us to focus, we have this picture in our minds of zeroing in on a thing, like a target. But if you really think about it, something else has to happen before the focus. You don't simply throw your attention out and hook the object you want to focus on-like walking up into a large group of people, trying to find a friend of yours who's there. You don't just bump straight into him or her, usually. Usually its a process: you work through the crowd of people, looking one way and then another, eliminating groups and individuals as you narrow down your search for your friend: you arrive at where your friend is, really, by a process of weeding out where your friend isn't."

In yoga we use dristhi, so while we hold an asana and settle the gaze at the tip of our fingers or at the navel, we must first gain awareness of the other surroundings, tune them out, to arrive at our focus on the fingertips. This is the process of "withdrawing the senses" from the outside world to a clear inner focus which is so helpful to clean our minds of unnecessary "stuff".
Breaking it down in easy steps:
Step 1:
Clean the 'outer' place up (whether its your apartment, room, studio, kitchen, work space….
When the outside is clean and tidy it reflects on the inside.
"Its'a a lot easier to find your friend in a group of ten people, especially if they are all lined up, than in a crow of a hundred all milling around. Less effort, to focus all day long. Focus is like food for he mind: the mind thrives on it, and so do the good inner winds"

Step 2:

Clean the 'inner' space up. 

It's a process of elimination, when we have cleared all the unnecessary things away, then the mind will be free to come inside and arrive at its own nature: concentration, contemplation, uninterrupted attention, and a healthy happy state of mind.
It's all a kind of cleanliness, in way: tidiness on the outside, tidiness on the inside"