One major thing to consider when choosing skirts is that where ever you put light/ bright colors appears larger. So, If you have wide hips or a large backside, and you want to minimize it, avoid light/ bright colored skirts (and trousers) and stick to basic neutrals. If on the other hand, you have a small backside but you want to draw attention to it, wear light/ bright colored skirts. One tip is that if you have more curves than you are comfortable displaying, you should try body shapers to help hold everything in.
If you are very curvy but want to draw attention away from, another trick is to choose skirts that have details that down play them. Examples are a simple black skirt, an a line shaped skirt, a full circle (swing) skirt and any skirt with vertical details like pleats, vertical stitches, and an elongated pocket. Another tip to draw attention away from your bottom half is to wear an interesting top to draw the eye.
If you want to add curves to a small bottom half, or to balance out a no waist figure, you can wear bright colors and shiny fabrics. Because they visually expand the your hips and backside. You can wear balloon skirts, printed fabrics, a line skirts and faded washes of denim skirts. These will help you look curvier than you are.
If you have a straight up and down figure, with no definable waist, wear smug pencil skirts. The tapering around the thigh creates an illusion of curves.
I hope I have helped you in becoming more stylish. Stay fabulous.