My best tip is to have a firm plan for what you are going to consume today. Do you mean to jump straight into a liquid fast? For most people it's easier to ease into fasting with 500 kcal worth of good, solid food.
Make sure you have plenty of tasty things to drink today, so that you do not get dehydrated, and so that you have something to fill your stomach with.
Good zero kcal drinks are coffee, tea and fizzy water/sugar free soda pop, because they feel more substantial and satisfying than plain water.
Good low kcal drinks are miso soup, bouillon cubes, low kcal hot chocolate and green smoothies made from salad vegetables.
Good nutritious drinks are soup, stock, milk and smoothies that aren't too sugary (because sugar will make you feel hungry).
Also protein shakes and meal replacement drinks, though personally I would rather eat real food if I'm going to have that many kcal anyway.
Once you have a firm plan of what and when to drink, you will find it much easier to put it out of your mind and focus on something else.