If you've already begun cutting out soda (which are 100% empty calories) that's already a good start. I wouldn't completely cut it out cold turkey, I know how cravings get especially when you think you CAN'T have something, but even if you save it for "only special occasions" or "only weekends" that's already a start. Plus at fast food places they'll generally hand you a water cup for free - you're saving a buck by not having the soda and getting something better to drink.
The "easy" way to get veggies into recipes is to substitute them for some of the meat. Examples: if I'm making Philly cheesesteak, instead of 1 lb of sliced steak I use 1/2 lb meat and 1 or 2 sliced portobello mushrooms (plus the onions and peppers of course). Cooking the mushrooms with the meat and it all pretty much looks and tastes the same in the end. And instead of serving it in a huge hoagie roll I load it up on a wheat flatbread and eat it like pizza. Or with sloppy joes, again instead of 1 lb of meat I'll do 2/3 lb, and then finely dice onions, carrots, mushrooms, cook them together in a homemade sauce, and then when serving I use smaller buns and serve it open faced so the plate looks fuller (which tricks your mind into thinking it's more food) and forces you to slow down as well which gives your stomach more time to register that it's been fed. And of course I'll have a veggie or fruit side along with that, like baked parsnip fries, roasted spiced broccoli, apple slices sprinkled with a little cinnamon.
Even if I make something super simple like mac and cheese out of a box (I crave weird things!) I throw in frozen mixed veggies like peas, corn, carrots while cooking. It doesn't take any extra time but it at least makes a junk lunch a little less "junky" plus it honestly makes it less boring too.
You don't have to cook frequently to make an impact. If you can manage just 1 time a week to start, that's already better than nothing. I also like to make extra portions (I have 2 in my household, I cook for 3 or 4) so I always know what's for lunch the next day. Things like soup are easy to make in even bigger batches and then refrigerate or even freeze for later. A crockpot is a magical thing for super busy people.
Obviously on school days it probably is easier to eat out (and half the time you're running around thinking gotta work on a paper, gotta go to library, need time to study), but even then, try to pick things that are smarter choices. If you start making it a habit to pause and think about what you're ordering it does get easier over time. Subway is always tricky because the perception is that it's always better than a burger, but if you get a footlong with all meat and extra cheese and mayo, that's not really better (salads are another trap... most salads are hidden calorie bombs due to the toppings and dressing).
Remember you don't have to force yourself to "eat well" ALL the time - if you're just dying for pepperoni pizza one day, have the pizza, don't feel bad about it - and once that craving is satisfied, pick something that's better for the next meal. You don't get anywhere getting mad at yourself for wanting that pizza.
I think it would also help a lot if you made some sort of basic schedule - we all tend to eat more when we're running around and unaware of time and then suddenly you're hungry and you're walking by a Cinnabon. I try to eat around the same time each day. I even generally have my cup of coffee around the same time each day. I always take the dogs out at the same time each day (they happily remind me if I'm even 5 min late). And then everything else I have to do just falls into the spaces in between, and life feels a little less hectic.
