I suggest a traditional quilt pattern incorporating a novelty I spy type fabric. That way it's classic enough to withstand changing trends as she ages, feels fun when she's little but not so childish that she will outgrow it in 10 years. I have a purple log cabin style quilt with cat fabrics that my grandma made for me when I was about 8 that I slept with until I grew up and got a bed too big for it.