Fasting: A Great Blessing!
Some non-comprehensive tips:
It is a blessing to the soul for a person to establish the practice of reading the Scripture, praying and fasting before his or her pre-marital years. You can just fast a meal to begin with... God will recognize your sincere effort with faith in Jesus the Christ. However, beware, if you determine to fast a meal, make sure you don't start and then quit due to a temptation. Be faithful in whatever you determine. The Lord is pleased in our faith and simple living, fasting is not something we have to do right away. We can learn to fast to bring us closer to the Lord. Fasting is generally a practice of self-denial of food with a respect of expecting a blessing from the Lord. A fast can be short such as missing lunch. It can be longer also, even for days at a time. Whatever the predetermined length, it must not be interrupted or discontinued.
NOT AFTER FATIGUE AND HUNGER: “Then Jesus called his disciples unto him, and said, I have compassion on the multitude, because they continue with me now three days, and have nothing to eat: and I will not send them away fasting, lest they faint in the way.” (Matthew 15:32)
Make sure your body is healthy: God wants us to be in good physical shape. We need to get nutrition from food. If you eat well, you may not even get sick. I haven't been sick for years, praise to the Lord.
If you know you are healthy, then you may fast; however, if you are not, then learn to eat and exercise properly until you know you are well and then you can learn to fast. It may take years for some to recover and get healthy if they have experienced diabetes or some other dreadful disease, so give yourself enough time. Actually, if medicine was taught properly and from a Christian perspective, people wouldn't be taking drugs to ease the symptoms; many would be experiencing recovery.
Fasting may be individually done before the Lord, and not men. Sometimes, it is done in groups for a specified reason.
SECRETLY AND REWARD: “That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly.” (Matthew 6:18)
Fasting is an aid to casting out demons.
REBUKING THE DEVIL: “Howbeit this kind goeth not out but by prayer and fasting.” (Matthew 17:21)
Faithfulness should be self-discerned before fasting. It is an abomination for a person of a false religion to fast. Remember, if we confess our sins, God forgives (1 John 1:9) us. Although fasting may help bring us to repentance, it is not a replacement for repentance. Many people in the falling away we live in think they can partially repent and have a great religious life. To their rebuke, religion is not what pleases God; a faithful relationship does! If a person is knowingly living in fornication, he or she should completely repent of it, and not fast until he or she is living in faith.
Links:
Breaking Clean from Partial Repentance
Health: The Land of Milk and Honey
Lukewarm: Curse of Partial Repentance
Refuting the Re-virginity/chastity Myth
Refuting the “Perpetual Virginity” and Re-virginity Doctrine
God Wants Prosperity for Christians
Mockery Will Not Escape God's Judgment