start incorporating healthier foods in by cutting out a little of what you don't think is as good for you.
so instead of having a cup of pasta with sauce, have 7/8 cup of pasta with sauce with 1/8 cup veggies mixed in. and as you find veggies that you like mixed in, scale up the amount of veggies and down the amount of pasta.
i like nachos and more often than not, it tend to be just the cheese and chips kind. so i started making myself either do the full kind [where i am getting beans and peppers and tomatoes and avocado and lettuce] or have some carrots with hot sauce along with the cheese and chips.
if you love burgers and fries, don't have them in the same meal. have the burger with a salad or a broth based veggie soup. perhaps bake the fries with some fish.
when you try fish, try them in something like fish tacos. you can chop up a filet of a mild tasting fish into bite sized pieces. the toss it in a little flour and spices, and cook it up in a little olive oil [i generally use about a Tablespoon]. you can serve it by itself this way or you can put into corn tortillas with pico and lettuce and a little cheese.
if you love pizza, start adding a veggie topping and decreasing the amount of cheese and meat on it. also, add a side salad.
if you love mashed potatoes, start adding dark leafy greens in halfway through cooking to steam. and don't add so much water you have to drain, add just enough to steam the potatoes and greens. then mash with a little milk or greek yogurt.
if you're having mac and cheese, add some veggies to it. cauliflower and broccoli are both great additions.
so again, the basic idea is to take something you like and add something you think is good for you to it. once you hit on something you can stand, increase the quantity of the good stuff and scale back the quantity of what you think you should be eating less of.
-google first. ask questions later.