this skirt is made with one yard of fabric for any size. this one i made for popi, i am making the same skirt for bee next. you can use a coordinating fabric for the ruffle and waistband if you want, sometimes i do, sometimes i don't. the waistband you use a yard of fabric and the width is up to the size of the elastic you use. you wan to make sure when you wake your waistband there is room for the elastic to go through. the ruffle, which you can use or not, is about 2 yards.
first i made the ruffle. the width depends on how much ruffle you want. fold your yardage in half giving yourself about a half inch for sewing, and that will be your ruffle width. i wanted about a 2 inch ruffle so the width i used was about 5 inches. i folded it in half and ironed it to make it stay and sewed the opening down with the largest width stitch on my machine all the way through without any back stitch. you take your thread end and ruche the fabric down to the other end making your ruffle till you have a little over a yard ruffle.
pin your ruffle to the bottom of the skirt. again, the length of the skirt is determined by who you are making it for, hold the fabric up to your child and see where it hits and add a couple inches for edges.
you then take the waistband fabric and sew it inside out on the edge and then you turn it right side out and iron it flat.
i had sewed the skirt together before putting the waistband on, but you don't have to. you pin the waist band on in the inside of the skirt and sew it on leaving the ends open. you can sew the skirt together now or before, just remember about the open ends.
i have a nifty elastic threading tool, but you can also put a safety pin on the end of your elastic to fish it through the waistband. just measure your child's waist to see how much elastic to use. make sure to leave a couple inches of elastic so to make it easier when you sew your elastic together. when you have fished it all through, pin the elastic together and sew. then you can hand sew the waistband ends together.