Satiety is apparently a complex mix including mental aspects but also chewing. Have you tried chewing more? Either "over chewing" (just keep each mouthful of food in your mouth longer and chew it to a complete pulp) or lower calorie foods that you physically have to work on more to actually eat (carrots, celery, ...)?

Water before eating may help you slow down too, which means your body can realise you're sated at an earlier point through the meal.

Just suggestions, YMMV, IANADietician and haven't fully researched these ideas scientifically (though they are based on research I've heard about in passing).