Here are some Bible verses about fasting shared by Biblestudytools.com:
5 Do not deprive each other except perhaps by mutual consent and for a time, so that you may devote yourselves to prayer. Then come together again so that Satan will not tempt you because of your lack of self-control.
12 “Even now,” declares the LORD, “return to me with all your heart, with fasting and weeping and mourning.” 13 Rend your heart and not your garments. Return to the LORD your God, for he is gracious and compassionate, slow to anger and abounding in love, and he relents from sending calamity.
16 “When you fast, do not look somber as the hypocrites do, for they disfigure their faces to show others they are fasting. Truly I tell you, they have received their reward in full. 17 But when you fast, put oil on your head and wash your face, 18 so that it will not be obvious to others that you are fasting, but only to your Father, who is unseen; and your Father, who sees what is done in secret, will reward you.
Fasting, from many years even before Christ, was a symbol of a person humbling him or her self to show God that he or she is sincere in seeking Gods blessings.
Here are some tips for fasting shared by Whatchristianswanttoknow.com.