Romans 10:17 So then faith cometh by hearing, and hearing by the word of God.
If you wonder why you do not have enough faith then you need to consider this verse. If you want more faith you need to hear more of the Word of God. You need to read it. You need to hear it preached. You need to be thinking, meditating, discussing, and living in His Word. As you do that you will grow in your faith.
The only way to have more faith in God is to know Him more and better. You will do that through His Word. You need to get into the Word of God and get the Word of God into you. As you do that then you will find your faith growing.
As you know more of the Bible you will know more of God. As you know more about Him and what He does then you will believe Him more and more.
Learn the Bible. Grow in your walk with God.