Start with one veggie -- red or green leaf lettuce is good. No other veggies for the time being. Chop the lettuce very fine (think a pencil eraser in 6-8 pieces). Sprinkle it on her pellets. Feed her the lettuce this way for about a week, or less if she starts eating it. She'll get enough by accident to get used to the taste, and then you can feed it in larger pieces and start on another veggie. Green bell pepper should be next. Then cilantro, but you might try just sitting her on your lap and feeding her cilantro -- most pigs love it.
When she will reliably eat lettuce, bell peppers and cilantro, you can add other things -- a slice of tomato, a baby carrot, endive, dill, parsley (not much parsley if she's over 6 months old), basil, corn husks and silks (all she'll eat, but strip the outer husks and silks off to get rid of the pesticides), zucchini or other summer squash, green beans.
You can teach her to eat fruit the same way, but fruit should be a treat only, a little bit a couple of times a week. It's too high in sugar for them.