Phytochemicals, fiber, filling low-calorie volume... try this for one week and you'll get it all.
1 Bag, 1 Week
Buy a one-pound bag of frozen vegetables on the weekend and make it disappear by Friday.
Why frozen? It's as good as fresh, they come in a variety of blends and can be flavored to suit your tastes, plus they require just a few minutes in the microwave or on the stove. Portion sizes be damned, just remove and prepare as much or little as you like when you eat a meal. (Eating large portions early in the week simply leaves less to consume later and vice-versa.) The bags typically cost just two bucks.
For guys and gals with sub-par vegetable intake, this is a cheap, no-brainer way to improve "dietary quality" (which has various definitions but adding whole veggies is certainly part of the picture).
Once this becomes a habit, try two bags per week, then three. You get the idea.
What Do You Get Out of It?
Phytochemicals that have all sorts of health and physique-enhancing effects, fiber, low-cal satiating volume when needed, and simply that nice little side dish to eat with your chicken breasts.
What may be best as far as a self-challenge is the simplicity of the goal: Buy the bag and eat it all this week. You could also do this with frozen fruit.