Nothing is more exciting or rewarding than sharing Jesus with someone else. Just simply sharing your testimony of how you gave your life to Jesus is a tremendous start.
The Holy Spirit made you a new creation when you made Jesus your Lord (Romans 5:5; 2 Corinthians 5:17). And your spirit man received the nature of God (including His love). But to walk in the power of God, you need to receive the Baptism in the Holy Spirit, which includes the ability to speak in other tongues. This ability is invaluable when you’re praying for those to whom you want to witness (Romans 8:26-27). You can only grow more effective as you read and meditate on His Word. Allow your faith to grow and do not hesitate to receive the gift of the Holy Spirit, and allow Him to work and pray through you.
Another huge asset in your witnessing is the boldness that comes from understanding that you are in right-standing with God. Right-standing is not something you can obtain by self-effort. Boldness to witness happens when you understand that in Jesus you have been made the righteousness of God (2 Corinthians 5:21; Romans 3:22). This gives you the assurance that He is on your side (Isaiah 32:17). It’s a benefit you’ve been given in Christ Jesus (Ephesians 3:12).
Any shyness will leave as you spend time in prayer and in God’s Word, and grow in the understanding of who you are in Jesus and the power of His Holy Spirit. You will not always have to go out and find people to witness to; they will start coming to you. Your very lifestyle—just the way you live your life each day for the Lord—will become a powerful example to the people you come in contact with, and they will want what you have!