REALLY need advice on eating healthier

I’m super picky and eat all sweets/carbs basically. I feel disgusting and need to change, but I hate most healthy food! I love fish (especially salmon), pasta, potatoes, cheese, pizza, and that pretty much sums it up. The only fruit I like is grapes and the only vegetable is corn. Can someone give me some ways to start a healthier lifestyle, maybe some ways to make these foods healthier? PLEASE HELP, I’ve struggled all my life :(