A few ...
When I consult with families of picky eaters we talk about getting them involved as much as possible.
Always give choices (about 2) so that they feel they are in control bout their fruit/veggies (food is one of the only things they have control over so being picky might just be exerting some of that control). Talk about the food groups (even as young as 4) and talk about how eating foods from all food gorups make our bodies healthy and keep us healthy and help us grow. We do a lot of that kind of talk here. So when dinner hits - offer 2 vegetable choices - at first it might just be a tablespoon full. Some kids do well with sticker charts and rewards like that. Maybe tracking at least X fruits a day etc..
Dole has a grat website with a fabulous kids cookbook. I ordered it for a whole class I recently taught an they were so excited!
There is reserach that supports you have to offer a food ~ 14 times before it might be accepted. This just means, don't give up. Keep a little of that food in your fridge and keep offering.
Also with summer, getting kids involved with planting and tending their own foods is huge. Food prep too - at 4 there are some things she can certainly help with.
Read food related books. There are some great ones out right now. Sam I Am is what we refer to at dinner time a lot. We also have Sam I Am awards for that person who does not think they will like it but then likes it, just like Sam. I will never, not ever eat a tomato is another cute story we reference. Here is an exhaustive list linked below.
In most of my classes we make fruit kebabs and this is a huge hit! I stick them in a melon shell turned so the inside is on the bottom and I use toothpicks and add tomato eyes, carrot nose and wahetver I find for a mouth. Grapes, strawberries, mandarin oranges, melon blass or chunks, pineaple chunks, you name it. The kebab sticks are poked all around it so it looks like crazy hair.
Anyway hope some of this helps. Child Magazine just had a big article about this very topic.
http://www.nal.usda.gov/fnic/pubs/bibs/gen/childlit.html