To increase your faith in God is not an exercise of mental will-power but rather it is a work of the Holy Spirit and the Word of God. The Bible says, “faith comes by hearing, and hearing by the word of God.” The more you read, hear and study the Word of God, the stronger your faith will become.
Belief alone is not faith. When you believe and take action based on what you believe, then that is faith. Everyone has faith in something. For instance, you believed that the chair you are sitting in would hold you so by faith you took the action of sitting down.
Likewise, you need to take action based on your faith in God’s Word. James tells us that faith without works is dead. So you need to take action based on what God’s Word says. By doing so, you will increase your faith.
Your faith in God acts as a shield against the attacks of the devil according to Ephesians 6. So build your faith by reading, hearing and applying God’s Word daily!