I siggest that yiu drink alot of water and eat healthy snacks often aprpx. Every 2-3 hours, say a cereal bar or a fruit
Do you chose not to eat plenty of vegetables because you don't like them, because it's inconvenient, or for some other reason?
If you don't like them...try hiding them in your foods. For instance, cauliflower in your mashed potatoes, or mixing veggies in your meatballs (for spaghetti)...you can even use spaghetti squash for noodles (really yummy). Instead of home baked potato chips, try kale, carrots, turnips, ect and bake them into chips. Or...JUICE them...you can hide all sorts of vegetables in fresh juice.
If you don't eat them for inconvenience (which is a problem our family has), pick one day and chop the heck out of some veggies and store them in the fridge. We have found that when they are available in the fridge, we eat them, If not, we pick other items. Taking an hour, one day a week, will allow you to chop and package an entire weeks worth of snacks. We also make a huge salad and store it in the fridge...that makes it super easy to add a salad to any meal. ( want a great, healthy dressing recipe?? Make your own. Example, tbsp olive oil, tbsp red wine vinegar, tsp honey, salt/pepper to taste, pinch of garlic powder...shake, shake, shake and drizzle...this stuff goes a LONG way, so be sparing at first).