How about trying "sweet" veggies? Yams, butternut squash, carrots, snap peas (just the pea if she doesn't like the pod), and corn though that's more like a treat nutrition wise. Most birds will naturally go for a sweet taste. Many sweet tasting veggies are orange/yellow, which are some of the most nutritious ones out there.
You can also get a chopper and chop mixed veggies (with foods she likes) so small that it would be hard to pick out certain items without accidentally ingesting the other stuff.
If she's a picky eater, make sure she's on a high quality natural pellet as her base nutrition. Though wide variety is optimal, remember also that she is NOT going to be a malnourished parrot unless all she gets is seed.
If you are really concerned (well, even if you're not) it's a good idea to take your bird periodically to the vet for a blood chemistry to see that all the organs are functioning properly as result of decent nutrition. Especially in older birds.
