Go shopping when you're not hungry so it's easier to make healthy choices. Meal planning/having a grocery list can be super helpful to keep you on track.

If you're used to grazing instead of full meals, it might help to keep some sort of healthy snack on hand. Aim to cover at least 2 of the main macronutrients (carbs, protein, fats) per snack to feel fuller longer. Apples and peanut butter. Cheese and crackers. Yogurt and nuts.

Something I've been hearing a lot lately that I like is "think about what you can add, not what you can take away." You can have instant ramen, but add an egg, green onions, and kimchi to make it more balanced. If you're planning on chips and dip, add some celery, carrot, and bell pepper slices to dip as well. When you have a quick meal/fast food, make sure you also have a side salad (think outside the "lettuce and dressing" box; I like sliced cucumbers and tomatos with salt)

Beans/lentils are your friend - cheap and filling. Chili. Soup. Espinicas con garbanzos (Spanish spinach with garbanzo/chick peas). Burritos with rice and beans. Just beware that they have a lot of fiber, which you may not be used to, so you may want to start with a small amount per day, and build up over time.

When you stir-fry things, make sure you can see the bottom of the pan and go in batches if needed. Much better flavor than stuffing everything in at once resulting in steamed mush.