What can I wear to complete these outfits?

For the cream skirt, stick with a simple top, tucked in. A tank top in a pastel color of your choosing would do nice, but you can choose a short sleeved shirt as well. For both skirts, just make sure the shirt is slim fitting. And when you tuck the shirt into the skirt, pull the skirt up, and let it sit at your wait, not hips. For the blue skirt, you could dress it up with any neutral shirt tucked in, with a pattern, or design because the skirt has no detail. You could also pick a white shirt, and wear a large bright necklace. If you're into the fashion belt, add a thin brown leather one to each outfit.