Don’t think about water and food, don’t research them online, don’t go to shops, don’t open fridge, don’t touch them. Whenever there’s a thought about water/food, become aware of it and move attention to what you’re doing. Fantasizing about water/food is not allowed. Accept lower efficiency, bad mood.
Have not experienced it with the 3 days fasts I have done. Do you usually have a lot of refined carbs in your diet? It may make it harder, I suppose. Also could be candida. This may not be a mental game for now (eventually it turns into one though, you will get into a flow state of you allow your cravings to pass for sure).
Usually one tolerates dry fasts much better than a water fast.