As a vegetarian, eating veggies comes with the territory lol. But if you're not having enough veggies already, I'd recommend switching to a cuisine which is veggie-heavy where you don't need/miss meat, like Indian/Asian/Mediterranean cuisines etc.

For fruits though, the key is to always have some at hand, in a convenient format, so that you're less likely to grab a bag of chips or something. For instance, with apples, you can cut them into pieces and apply lemon juice so that it doesn't oxidize, and then put it in a small airtight box next to wherever you spend most of your time (could be your desk/couch/bed etc). Same thing with oranges, peel em and put it in an airtight container. Other fruits don't need such prep work so you can alternate with them, eg grapes or bananas. And the trick is again, always have them nearby you so you're more likely to reach out to them than for junk food. And to get into the habit of this, make it a part of your daily routine. Like for me, I make a smoothie the first thing in the morning, and as part of that routine, I also prep my fruit-box for the day.