I recently came across a really cool
Tumbler Skirt Tutorial that I just had to make. I must give most of the credit to the original tutorial author, but I am re-writing it here for adult sizes (as the original skirt fits a little girl).
Here is a skirt I made this week. Sorry for the poor image quality, I took the pic with my cellphone, which is the only camera I have right now.

This skirt is made of trapezoid-shaped quilt blocks, with the finished bottom width of each piece being twice that of the finished top width. The size of trapezoid quilt blocks I prefer to use are 4" wide at the top, 7.5" wide at the bottom, and 7.5" long. This is just a teensy bit tricky to explain; when each row of quilt blocks is stitched together, the narrow tops of two quilt blocks will be stitched to the wider bottom of one quilt block in the row above it. Each row has twice as many quilt blocks as the one above it. With a 1/4" seam allowance on each side, the finished width of these quilt blocks will be 3.5" at the top, and 7" at the bottom.
The reason I decided to go with this size of quilt block is because you can get 6 blocks out of a one-quarter yard length of 44/45" wide fabric (flipped side-by-side across the width)... or out of one fat quarter (2 rows of 3 each).
Now, to figure out how many quilt blocks you need, measure your waist, and divide this number by 3.5". Round up to the next whole number. This is how many blocks will be in the top tier. Each row has twice as many blocks as the one above it, so you need to multiply this number by 7 (1+2+4) to find the total number of quilt blocks.
Example: my waist is 30".
30 ÷ 3.5 = 8.57, rounded up = 9.
9 × 7 =
63 quilt blocks.
Divide this number by 6 to find the number of 1/4 yd lengths or fat quarters you will need. For my example, I will need 11 quarter-yard lengths of fabric or 11 fat quarters to make my skirt. Or, if I want to use fabric scraps I already have, I could scrounge around until I find enough to make 63 pieces. Any extra bit of fabric can be used to make a matching headband, or decorative fabric flowers.
For the skirt I am making here, I bought 1/2 yard each of 4 coordinating fabrics, and 3/4 yd of a 5th coordinating fabric, to make my 11 quarter-yard pieces. (I have a stack of fat quarters waiting to be made into another skirt sometime in the future).
*Note: the finished length of this skirt is 21". You can make the skirt any length you want by lengthening the pieces, but this will affect the length of fabric you will need. Go longer than 8" (1/4 yd is 9" but I am including shrinkage allowance) and you will need more than 1/4 yd for each length of fabric, or you can't get the 6 pieces out of fat quarters. You could always make more tiers, but that would make for an extremely full skirt- this one is already 240" wide at the hem- and it will mean a lot more fabric, a lot more quilt blocks, and a lot more sewing. Just play around with the numbers, and cut test pieces out of scrap paper to try out the layout.Cut a trapezoid template out of paper, to use for cutting out your pieces. I highly recommend a cutting mat and rotary cutter, but you can always trace the shapes with a pencil and cut them out with scissors.
If there is a white strip of selvege along the edge of the fabric, go ahead and cut it off. Line the template up against one end of the fabric.

Line up your straight cutting edge along the sides of the template piece. Cut off the scrap piece at the very end, and discard. Cut out the quilt block, being careful not to cut the template piece itself, and don't let the straight edge shift.

Next,
flip the template upside-down and line it up against the new edge of the fabric. (Have I mentioned that it's best to have a fabric without a one-way design? Well, now I have).

Continue until you have all your pieces cut out, and have fun arranging the sequence you'd like them to be in.
Start stitching the pieces for the top tier together, but do not stitch it into a full circle yet... leave the last seam undone so you can insert the zipper. Continue with the 2nd and 3rd tiers.
Attach the bottom of the first tier to the top of the second tier, matching the seams of the top tier with every other seam on the second tier. You may need to ease the fabric a bit, because it may be slightly off (as happens to me, haha). Repeat to attach the 2nd tier to the 3rd tier.
Sew the "back" seam from the bottom, up to the seamline where the 1st and 2nd tier meet. Insert the zipper on the first tier, following the manufacturer's directions.
The *easiest* way to fit the skirt at the top is to make a little dart on each side of the waist edge. For example, if I make the skirt for a 30" waist, the finished top edge will be around 31.5". I'd leave 1/2" for ease, and make a little 1/4" dart on a seam at each side (which would take 1/2" off each side, for a total of 1").
I found that the easiest way (for me) to finish the skirt was to bind the edges with extra-wide double fold bias tape, in a coordinating color. I used 3 packages; they are 3 yards long each, and the bottom hem was almost 7 yards wide. This gave me enough to use around the bottom hem, with enough left over to bind the waistband edge. Attach a hook & eye to the waistband trim. You can also finish the hem by folding it under about 1/4", but it may be a little tricky. I prefer the look of the bias tape.
I will update this tutorial with a few more construction photos sometime in the next couple weeks, as I finish making the skirt with the quilt blocks I am cutting out in the above photos. I finished the pink & black & white skirt earlier today, and was so pleased with how it came out, that I decided to quickly throw this tutorial together. I am at the end of winter break right now, and getting ready for college to start again next week, so I'm trying to finish this skirt along with 100 other things around the house.