Methods of Silent Witnessing
Countenance, always wear a smile
Show courtesy when dealing with others
Patience in your dealing with others
Be on time
Always be honest
Compassion towards others
Eating habits, don't be gluttonous
One's true character is always on display as a silent witness to others in conversation and actions, and as such, we should try to display the godly character working within us.
There are other methods of silent witnessing not listed, see if you can come up with a few of your own.