Many Christians lament their lack of witness to others. Others forcibly witness to the detriment of the unbeliever.
I say, stop. Stop worrying about your lack of witness and stop the forced witness of men. You carry God's Holy Spirit inside of you wherever you go, therefore, where you go; so too goes God's Spirit.
The prophets, leaders and apostles of the Old and New Testament were all given one command - "Go!" When Moses fretted about what he was to say or whether the people would believe him, God's answer was - "Go!" When the prophet explained to God that he could not speak to the people because of his impediment, God's answer was - "Go!" After Saul's conversion, Paul went wherever the Spirit led.
Whether you spend your day in an office, teaching a class room full of children, behind a counter helping customers, or fighting in a foreign land, you are a witness to that which is in you. Believe me when I say that the people around you know that you are different. Some will reach out to that difference and some will reject that difference, but no one will be oblivious to that difference.
Do not fret that you cannot bring Bibles to the people in foreign lands or that you are forbidden to speak about God at the workplace. God is bigger than them. God is bigger than you. He only needs us to show up.
Pray a simple prayer - "Please Father, let me be a witness to someone today." or "Please Father, save -----." Then go knowing that God is in charge of the spread of His Word. He was always in charge. How else could one seemingly insignificant Man spread the Word of God throughout the world in two centuries? Paul was saved without any human witness, and so have countless others.
Our charge is to Let God work through us. If we strive to work ourselves, then we have succumbed to the enemy's pit of salvation, religion and pride in our own works. Salvation was purchased by the works of our Savior; not by ours.