Prayer can be enhanced by fasting.
And now, my beloved brethren, I would that ye should come unto Christ, who is the Holy One of Israel, and partake of his salvation, and the power of his redemption. Yea, come unto him, and offer your whole souls as an offering unto him, and continue in fasting and praying, and endure to the end; and as the Lord liveth ye will be saved.
However there is such a thing as overdoing. A man may fast and pray till he kills himself; and there isn’t any necessity for it; nor wisdom in it. … The Lord can hear a simple prayer, offered in faith, in half a dozen words, and he will recognize fasting that may not continue more than twenty-four hours, just as readily and as effectually as He will answer a prayer of a thousand words and fasting for a month.
Source: Omni 1:26; The Book of Mormon: Another Testament of Jesus Christ