How do I preach the gospel? Meaning, where should I do it and what should I say? If I do it at work, I would probably get fired. Do I just go up to complete strangers on the street, in stores, etc? I have severe anxiety, and I'm not articulate, but those are not excuses in Jesus' eyes. Jesus commanded the disciples and apostles to preach the word, but not enough Christians do it today.
What often happens is that we think the only way to teach someone the gospel is to tell them from beginning to end. But God speaks of it as planting seeds and watering them. "I planted, Apollos watered, but God gave the increase. So then neither he who plants is anything, nor he who waters, but God who gives the increase" (I Corinthians 3:6-7). There are times you can have long discussions, but before that happens, often it takes a series of planting seeds and watering them.
Yes, if you spent an hour at work talking about the Bible, your bosses would be annoyed about the lack of productivity. But say when someone mentions that they are really worried about some future event, you can mention that Jesus said in Matthew 6:34 that there is enough problems in each day without having to borrow problems from the future. Someone might mention their child is sick and you can say, "I'll be sure to pray for him at lunch." Each is a seed directing the person's thoughts to God and His Word. Your example becomes a beacon. "Let your light so shine before men, that they may see your good works and glorify your Father in heaven" (Matthew 5:16).
Are you always going to know what to say? Probably not. If you are like me, you'll spend times hours or days later thinking, "I should have mentioned this ..." That is fine. It is a part of the learning and growth. What I started doing is writing verses with short notes in the front and back of my Bible, so I could remember and find an answer to a common problem quickly. After many years, I have most of them memorized.
If someone wants to know more, invited them to join you at lunch or met sometime after work. Talk about the Bible with them. And when you run into a topic you never thought about, ask if you can get back to them later because you need to think about it more. This then gives you an opportunity to grow as well.