I’m a super picky eater & I need advice about what foods to eat. PLEASE HELP

I always eat sweets and candies and it makes me feel really gross and unhealthy. It doesn’t affect my body and I like never gain weight. But I really need to start taking care of my body and eating right. The only vegetable I like is corn, and the only fruit I like is grapes. I hate most meats, but I like fish. I love potatoes and pasta. I also really love cheese. Anyone have any healthy suggestions I can try? Like something to mix veggies with to make them taste better? I really want to have a better diet. Please comment, anything helps!