In preparation for this special time with God, I strongly urge you to examine your heart, and detect any unconfessed sin. Scripture records that God always requires His people to repent of their sins before He will hear their prayers. King David said:
Come and hear, all of you who reverence the Lord, and I will tell you what he did for me: For I cried to him for help, with praises ready on my tongue. He would not have listened if I had not confessed my sins. But he listened! He heard my prayer! He paid attention to it!
Blessed be God who didn't turn away when I was praying, and didn't refuse me his kindness and love. (Psalm 66:16-20)
In your prayers, confess not only obvious sins, but less obvious ones as well. The sins of omission as well as the sins of commission experiences. These may be experiences leaving your first love for our Lord: worldly-mindedness, self-centeredness, spiritual indifference, and unwillingness to share your faith in Christ with others, not spending sufficient time in God's Word and in prayer, a poor relationship with your spouse, your children, your pastor, or other members of your church.
Another great way to prepare for your fast is to practice what I call “Spiritual Breathing.” The concept is simple, but it has changed my own life and that of millions of others.
Like physical breathing, Spiritual Breathing is a process of exhaling the impure and inhaling the pure. If you knowingly sin, breathe spiritually to restore the fullness of God's Holy Spirit in your life. You exhale by confessing your sins immediately when you become aware of them, and you inhale by inviting the Holy Spirit to re-take control of your life. As an act of faith, trust Him to empower you. During the fast, spiritual breathing-constant reliance on the Holy Spirit-will enable you to resist temptation, not only to sin but to abandon your fast.
Although fasting is primarily a spiritual discipline, it begins in the physical realm. You should not fast without specific physical preparation.
If you plan on fasting for several days, you will find it helpful to begin by eating smaller meals before you abstain altogether. Resist the urge to have that “last big feast” before the fast. Cutting down on your meals a few days before you begin the fast will signal your mind, stomach, and appetite that less food is acceptable.
Some health professionals suggest eating only raw foods for two days before starting a fast. I also recommend weaning yourself off caffeine and sugar products to ease your initial hunger or discomfort at the early stages of your fast.