You must have eight 8-ounce glasses of water each day. Water facilitates weight loss and helps you to stay healthy and regular when you are on a diet. Use ice water with a piece of lemon or lime if you find it difficult to drink the required amount, or use seltzer.
Avoid artificially sweetened beverages. Up to two cups of coffee or tea are permitted, black coffee preferred. If you can't drink it black, a teaspoon of Half-and-Half will only add about 8 calories. You can also use herb teas in moderation, but I would avoid, for daily use, those that have laxative qualities. Try low-salt bouillons for a change (or make your own with meat or vegetable stock and added vegetables).
Food preparation and size of servings
Prepare your food simply without adding fat during the 600-calorie rotation, and use only the very small amounts of fat prescribed in the 900- and 1200-calorie rotations. Learn to use herbs and spices in place of salt.
If you dislike weighing, measuring, and counting calories as much as I do, then, for convenience, all you need to remember when you prepare foods your own way, or when eating out, is that you will tend to be within the dietary guidelines when you choose standard, or moderate, "restaurant" portions such as you will find at a cafeteria.
If you do not have a good idea of serving sizes, it is worth your buying a scale and other measuring implements and measuring for a few days. Then you will have portion sizes stored in your memory, and you can discontinue the practice.