There's alot of ways people witness to nonbelievers, and unfortunately alot of us don't know the best methods for doing that. We've all probably been in an argument sometime in our life, over something big or small, and we'll probably get in a few more before we die. Unfortunately most of us don't argue the best way, which I did a blog post over on the Bible World app.
Another way we witness is by inviting people to church, which you should do, but its ineffective. In a survey they did over that, it was determined that 3/5 people invited to church never go in their whole life. Inviting people to church is good, but that should not be your way to witness, because over half the people you invite won't go.
One of the best ways proven to witness is something called "Missional Living." In the best terms, its taking what the church is suppose to be and carrying it with you. It showing to others what GOD and Jesus do in you life. Its directly impacting someones life with the glory of GOD.
For some places it could helping the single mom with food or money, taking food yourself to those who need it, maybe even hanging out at a nursing home with people because some of them don't even have family visit them. It's doing what Jesus would do, and not doing what he wouldn't do. So may GOD be with us, as we go through life as a missionary for GOD.