According to most experts, the best dietary advice for people with psoriasis is the same as for anyone else: Eat a diet low in fats and sweets and high in fruits and vegetables, lean meats or other proteins like beans and legumes. While you're at it, get regular exercise -- being overweight can make psoriasis worse and keep your medication from working like it should. Watch how much you drink; alcohol can also aggravate psoriasis.
Still, you shouldn't ignore your own experience with psoriasis. If your skin gets worse after you eat certain foods, then stop eating them and see what happens. That food could be a trigger for you.