It requires a huge mental shift. I'm not managing it at the moment but have done for as long as a couple of years in the past and know that if I could just do it for 3 months I could stick to it.
You have to get away from the idea that every meal has a large serving of a white starchy carb (bread, rice, pasta etc). You have to gradually reduce portion sizes. You have to swap calorie laden snacks for fruit and salary.
Initially yep, you feel hungry! Your body expects more because you have taught it to, it doesnt mean it needs more.
After about 3-4 weeks you genuinely adapt.
When I've done it successfully my menu for a day has looked like this:
Breakfast: skimmed milk porridge. 4 tbsp rolled oats & 120ml skim milk, plus blueberries or apple: 150 cals
Snack: fruit 50 calories
Lunch: sainsburys minestrone soup 600g. The pot contains two servings, 140 cals each. I actually eat both, one at about half 11, one at about half 1. I find that way it's a satisfying volume, but is less calories than a sandwich. 280cals total.
Snack: 4pm is my weakest time of day for snacking. I try and stick to salad (beetroot, carrot, celery, pepper, cucumber or tomatoes) - 60 calories or so But occasionally I give in and have biscuits etc - 120.
This leaves 900 calories for a main meal, which honestly is loads!