Sleep and meditation. Try to avoid high intensity exercising like running and weight-lifting. The more your body is working, the more energy you'll lose. Take the time to relax, stretch (keeps your blood circulation to better remove toxins), and use the time to reflect. Ask yourself why you're doing this, and empower your will to finish. Drink lots of water, nap, and go to bed early. Avoid watching TV because it'll disrupt your consciousness and make you hungry (due to all the food commercials).
You’ve probably come across all kinds of cleansing and detox programs online. There is a whole industry based around selling these plans and supplies to people trying to live healthier. Unfortunately, doctors largely agree that most of these plans have no real health benefits. They might even be harmful. It's best to skip them and follow a healthier lifestyle instead.