I don't know how I could stand it before I discovered this technique on my serger! Amazing! Supplies:
Fabric- a lightweight or normal woven. You might experiment with a lightweight denim.
You'll need a yard for a toddler/child skirt with 4 tiers.
Elastic for the waistband
Serger & Sewing Machine
You'll only need one measurement!! The child's waist + 1/2 again = ____ Step 1:
Take your yard of fabric and cut strips about 5 inches wide. If you're using a woven, it might even be easier to rip the strips. Cut a small snip where you want the fabric to rip at and just rip it apart gently. Wovens generally give straight lines this way. You should do this along the length of the fabric rather than the width. Step 2:
Take one strip to be the waistband. Cut it at the measurement above (waist + 1/2 again). Serge both long sides of the strip.
Set aside. Step 3:
Sew the remaining strips together at the short ends to create one huge long strip. Serge it normally all along one long side. Step 4:
Now, you might need to check your manual to see specifically how to set your serger to gather. On mine, I simply need to turn the differential up to 2 and turn the needle tension up to 5. If, after following the directions for your serger, it's not gathering enough, try turning up the differential more, or mess with the needle and looper tension a little. I noticed a big difference between having my needle tension at 4 or at 5!! 5 was much more gathered! Step 5:
With these new settings, serge the entire length of the long strip on the un-serged side, so that it gathers up. Step 6:
Now take your waistband strip and fold over one long edge about 1/2 to 3/4 inch and sew. This will be your elastic casing. Step 7:
Take your waistband strip and the gathered edge of your super long strip. Match them up with right sides together and sew with a 1/4 inch seam as long as the waistband strip. I found it easiest to sew with the ungathered fabric on the bottom, and the gathered on the top. This allows you to position the gathers as you sew. Cut the rest of the long strip off. I like to leave a little room, like 1/2 an inch after the end of the bottom fabric.
Step 8:
Clip threads and then start again, only this time, the tier you just sewed on will be on the bottom! You should be sewing the gathered edge of the long strip to the un-gathered edge of the bottom-most tier. Continue until you have as many tiers as you need or you run out of fabric! Step 9:
Measure out the elastic you need (I use the waist measurement exactly) and thread it through the casing at the top of the skirt, leaving a tiny bit of the ends sticking out. Pin them so they won't get lost inside. Step 10:
Lay out the skirt in half with the raw edges together. See how it makes a nice triangle shape out on the folded edge? Serge from the open ends of the waistband down to the bottom of the skirt so that it makes that same shape. Catch the elastic in the serging, but DO NOT serge over the pins- take them out first!! Voila! Skirt finished! Admire your handiwork!! You can hem the bottom if you want, but I've been just leaving them with the serging. I kind of like it.... and its easier.

I was thinking about this- and if you do it right, this skirt can last a really long time. Kiddos don't really add inches out as they grow, they mostly go up- so if you're making this for your 4T daughter, measure the waist of a pair of 6 pants or skirt and make the top tier based on that, then you just have to add an extra tier as she grows, especially easy if you just leave the bottom serged, and not hemmed, but even with hemming, just rip out the stitches and then attach!