Army green, cream and brown, aka earthy tones, that's what came to mind. Using the same brown as her horns or eyes might help as well. Seems I'm not the only one having trouble with colors lately. Look on color lovers for pallets.
Think about what she's like. What's her personality? What colors does she like? What colors the clothes from her world normally are. (Purple was hard to come by back then in our world. I think.) Does she need to blend in? What do people normally expect her to wear?