Make it clear what you want to accomplish. "Losing weight" isn't specific enough. "I will weigh 150 pounds in one year" is a specific goal. Make sure your goal is reasonable. Don't set a goal to lose 100 pounds in 2 months. This is unhealthy and crash dieting such as this is known to fail. When quitting certain drug addictions, you need to wean yourself off the drug. If you have a physical addiction, quitting a drug completely from this day on may result in harmful side effects. Cutting down on use over time will limit side effects, may be more likely to succeed and thus may be more reasonable.