While on a workshop of sewing and tabletweaving and so, one boy asked me to make him a pair of breeches. The leader of the workshop helped me with a pattern, which was very easy.
Two rectangles of the width of the thigh's perimeter, one about 8 cm. The future user showed me the desired length of the leg, then I measured the distance between his something and the lower end of the trouser-leg.
Then it was easy. Hand-sewn, the seams folded to look like French seams (I pressed it flat, folded the two parts to the middle axis and put together, pinned) and covered with a serging stitch.
The hole for a string has been buttonhole stitched, which I'm not particularly good at yet :-) At the sides I was changing the position of the thread slightly because of the rough fabric - so that it wouldn't fray out.
The breeches. Nice, simple, fast:-) By the way, I didn't fold the lower edge, it was the end of the canvas (on purpose).