I'm in my late twenties.
How do I get enough vegetables and fruits? I cheat and stuff them in where ever I can. For example, when I make spaghetti or stew, I puree a bag of frozen veggies or an onion and green pepper to use as a thickener (works great if you don't have six hours to simmer the stuff). I make strawberry smoothies for us after working out (1 tbl honey, cup or two of milk, bag of frozen strawberries).
I make a lot of spaghetti -- tomato is a fruit but if you use a lot of meat nobody can tell.
I serve some sort of frozen veggie with every meal, too. I owe my continued existence to Mr. Birdseye and whoever invented the freezer.
I try to buy fresh when the gourmet grocery store has stuff in season, but organic is too expensive and a lot of the veggies we like are too expensive anyway ($1.99 for a green pepper the size of a golf ball? Yeah. No.) around here. Bananas usually end up as banana bread.
Growing up, my parents taught us that no veggie was a good veggie unless it had Butter! on it. So I'm teaching myself not to need butter to enjoy the flavor of vegetables -- I use marinades, roasting, grilling, all sorts of methods.
The number of servings I get depends on what you mean by "a serving" and if you count jelly as as a fruit. I read somewhere that servings are roughly fist-sized for many foods; if so, probably three or four if you don't count my usual pb&j sandwich?