Faith

According to Webster's dictionary faith is:

1. Belief and trust in and loyalty to God
2. Belief in the traditional doctrines of a religion
3. Firm belief in something for which there is no proof
4. Complete trust
5. Something that is believed especially with strong conviction

Hebrews 11:1 puts it this way:

NOW FAITH is the assurance (the confirmation, the title deed) of the things [we] hope for, being the proof of things [we] do not see and the conviction of their reality [faith perceiving as real fact what is not revealed to the senses].
Hebrews 11:1 AMP

The Word of God can increase your faith. Faith indeed comes by the Word of God:

So then faith cometh by hearing, and hearing by the word of God.
Romans 10:17

Faith comes, enters your heart, your very being, through the hearing of the Word of God. There are several ways we can receive the Word of God:

Preaching - But what saith it? The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach;
Romans 10:8

Through the written Word - Then opened he their understanding, that they might understand the Scriptures,
Luke 24:45

In times of prayer - Call unto me, and I will answer thee, and show thee great and mighty things, which thou knowest not.
Jeremiah 33:3

A word of exhortation by another believer - Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord.
Colossians 3:16

In dreams or visions - By faith Enoch was translated that he should not see death; and was not found, because God had translated him: for before his translation he had this testimony, that he pleased God. But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.
Hebrews 11:5-6

Audible Voice of God - And he fell to the earth, and heard a voice saying unto him, Saul, Saul, why persecutest thou me? And he said, Who art thou, Lord? And the Lord said, I am Jesus whom thou persecutest: it is hard for thee to kick against the pricks. And he trembling and astonished said, Lord, what wilt thou have me to do? And the Lord said unto him, Arise, and go into the city, and it shall be told thee what thou must do.
Acts 9:4-6