She's old enough now to help with food so I would start there. Encourage her to taste as you go, start with things like baking, or making teeny tiny sandwiches with soft fillings.
Maybe yoghurt, fruit, all cut up super small. We had tea parties when one of our grandchildren was a poor eater and it wasn't about getting volume down them but tasting things.
Some nutritionist believe that a schedule is important and that children should know that they eat at certain times of the day. That's certainly true of one of our grandchildren.
I think also , use 'sneaky' ways of getting them to eat- my daughter makes fruit juice icelollies for instance or chocolate milk lollies.
Good luck !!