"How should I witness to my coworkers?"
When we interact with people on a daily basis, we have many opportunities for sharing our faith. First, be sure you are respectful to your employer and set a good example in your work ethic by working "as to the Lord" (Colossians 3:23).
When others around you grumble and complain, if you have a calm, forgiving, steadfast spirit, it will make an impression. As you respond in a Christ-like way to angry coworkers and stressful circumstances, people will see a difference in your life. Always be friendly and courteous, and show genuine interest in your coworkers’ lives. Invite them out to lunch to get better acquainted. Share their joys and sorrows by congratulating them in their good times and offering to pray for them in their bad times.
Be sure you do pray for them, then follow up by asking them about the situation you prayed for. They will be moved by your concern. If coworkers are discussing what they did during the previous weekend, you can share your excitement about attending church services or a special church event. Ask others if they have any plans for celebrating Christmas or Easter; be nonjudgmental of their answer, but be ready (if asked) to explain why you celebrate as you do.
Displaying a favorite Scripture or a devotional calendar, or reading your Bible during lunchtime, may prompt others to inquire about your faith. Bringing home-baked goods or leaving a small gift with a note on a coworker’s desk can sometimes have a greater impact than a thousand eloquent sermons. We can show our faith by our works. Others may not like a tree of righteousness, but they cannot help but like its fruit. Pray for opportunities to share the gospel, being careful not to infringe on your boss’s time.