As discussed , Triangular Body Shape women will have heavier Lower body as compared to their upper body.
The aim while buying skirts is to reduce the visual volume on the lower body.
Wear prints that are spread throughout the garment or prints and patterns on the lower hem of the skirt. Try uneven hemlines so that the attention goes away from the heavier lower body to the clothing silhouette.
If you have heavier outer thighs, than avoid hosiery or spandex as fabric and prefer more cottons, cotton blend, linen, Khakhi and such fabrics that don’t stick to the body.