Longer nails: As it is, the nail colors are hard to see, if you made the nails a little wider and longer the colors would show up way better!
Hair highlights: either add hair styles that have secondary colors built in, or use two different shades of the same color. Another idea would be to have a primary hair color, and an option to add a secondary hair color of your choice for highlights or dip dye or ombré effects.
Clothing Outer layer: jackets! Shrugs! Cover ups! Coats! Wraps! Separate the jackets from the tops and dresses and make it a different clothing category for WAY more outfit options.