Just some random thoughts in no particular order.
Here's a recipe I like for brussels sprouts: http://www.marthastewart.com/355776/brussels-sprouts-vinegar-glazed-red-onions?backto=true&backtourl=/photogallery/brussels-sprouts-recipes#slide_4
I have to agree with Iris. Spinach and kale have very strong flavors and probably will take some getting used to. Broccoli and brussels sprouts are up there, too. Why not start out with some of the more mild vegetables, like peas and corn and carrots and green beans?
Try adding a flavor to a vegetable to counteract the vegetableness of it all. Squirt some lemon on green beans. Add some ginger and a bit of brown sugar or honey to cooked carrots. Cook peas with onions.
Along the same lines, you might like some raw vegetables if you can find the right dip. Carrot and celery sticks with ranch dressing. Red pepper slices with hummus. Celery with peanut butter.
Roasting vegetables is said to bring out their sweetness. You could try roasting a pan of potatoes, carrots and onions. Peel the carrots and cut into sticks. Wash the potatoes and cut into chunks. You could peel the potatoes if you'd rather. Cut the onions into quarters. Toss them all in a bit of olive oil. Sprinkle some salt and pepper on them if you'd like, or a bit of rosemary. Put in a roasting pan and cook for 40 minutes or so at 350-400 degrees. You can turn everything over at the middle point, but you don't have to. They are done when a fork pierces a large potato chunk easily.
There's a difference in texture between fresh, frozen and canned vegetables. While you do lose a small amount of nutrients in freezing and canning vegetables, you don't lose everything--they are still a valid choice for healthy eating. Experiment. You may find that you like canned corn better than fresh or frozen, and frozen green beans over canned or fresh. (In fact, I know a family where this is the case. The mom just shrugs and is happy that the kids will at least eat some vegetables.)
Different cooking methods affect texture as well, for some vegetables, as well as flavor. A friend of mine cannot eat mashed or baked potatoes, but loves scalloped potatoes, and french fries and roast potatoes. So the best thing to do is experiment as much as you can.
You don't have to like all vegetables. I'm not a huge fan of turnips and parsnips. I didn't like brussels sprouts until I was in my 30s.