Consider fasting in a broader context than just food. The discipline of saying NO for a short time to something we cling to makes saying NO to other things easier. Think of coffee, chocolate, TV, computers, iPhones. If you have never fasted before, try a 12 hour fast initially. Spend a moment or two in prayer each time the craving pulls. Although it is ideally a private decision between you and God, challenging one or two others to team up with you for the same time period can be helpful.