Here are a few ways I sneak in more veggies:

Add them to recipes that don't call for them, for instance...
- if your pasta lacks vegetables other than the tomato in the sauce, throw in some steamed broccoli (a very great veggie to incorporate more of) and/or toss some red peppers into the cooking tomato sauce.
- if your stir fry is mostly onion, garlic, and bean sprouts (which are very good for you, by the way), throw in some extra veggies. anything you have lying around will probably work, just remember to throw in slow-cooking or larger vegetables earlier so they'll cook better.
- even if there are vegetables in your recipe, add more. either increase the amount called for or toss in something else. experiment with whatever you have in your fridge or buy extra of your favourite vegetables.

Add them as a side...
- I for one LOVE adding roasted vegetables as a side - it's way tastier than just steaming them.
- throw together a salad with some more interesting ingredients, skip the iceberg lettuce (try spinach or mixed greens instead) or if you insist on iceberg incorporate some radicchio or arugula to get more nutrients out of it.

Eat them for snacks...
- a standard answer and one you many have thought of is to eat cut up pieces of vegetables. don't bother with celery which is mostly water. i prefer pieces of broccoli, red peppers, and baby carrots.
- take a handful of cherry tomatoes to work and eat them as snacks. oh wait, i think tomatoes are technically fruit. oops.

Good luck.