I used for these short bloomers: light weight cotton, 2 cm wide elastic for the waistline and 1,5 cm wide elastic for the legs, some ribbon.
1: 1/2 of waist measurement, or of where you want the bloomers to sit + 10 cm.
2: 9 cm (front of the bloomers)
3: 10 cm (back of the bloomers)
4: desired length + 10 cm
5. 26 cm
6. should be bigger than the circumference of the thigh. Mine ended up 20 cm bigger.
The fabric should be cut right sides together.
After cutting the fabric, sew the edges together:
Now it looks like a big pair of shorts
For the elastic case I marked 1 cm from the edge and from there, on the waist line, marked about 2,5 cm.
On the legs I marked 1 cm from the edges and from there 2 cm.
I folded the marked lines, sewed them leaving a space to insert the elastic. After inserting the elastic close the gap that was left.
...and that was it!