Here's a few tips that helped me..
Re-organize your pantry and fridge. Since the South Beach Diet limits carbohydrates during phase one, before starting the eating plan, purge your pantry and refrigerator of breads, cereals, chips, crackers, sweets and other off-limits foods to help you succeed, especially if you are a carb-lover. If the carbs aren't there to tempt you, success will be that much easier. Give it away to friends or throw it out, and steer clear from the snacks aisle at the grocery!!
And like cottagebythesea said, make a grocery list to restock, and plan meals ahead! grab a serving of nuts, cashews or sugar-free gelatin.. I would suggest pre-dividing portions of nuts into baggies when you first buy it.. it would help you avoid indulging in them too much. Another good idea might be to prepare food ahead of time, so then there's no excuse for you to reach for junk food, and fill up on those veggies!!
Drink lots of water or tea! It might make you refrain from reaching for those salty and sweet snacks. It's a really good idea to let the ones who live with you know what phase one is, that way, you'll be held accountable, and they might even stop you from reaching for those carbs! Anyways, really hope you get back on track and goodluck!!