Waistband (The Correct Way)
Lay the jeans flat on a table or the floor. Twist the waistband 1/3 of its width, so it looks like in this picture. This is the easiest way of getting both the front and back side aligned to each other. Measure the top of the waistband and double this measurement.
Waistband (The Wrong Way)
Do NOT measure the waistband like this. Your measurement will be too small and you will end up with a pair of jeans that will not close.
Thigh
Measure the thigh from the crotch to the side across the fabric. Make sure to measure the entire width (not only from inseam to outseam).
Knee
Measure 35 cm from crotch down the inseam; this is where you measure the knee. Measure the knee from side to side across the fabric. Make sure to measure the entire width (not only from inseam to outseam).
Bottom
Measure the bottom from side to side. Make sure to measure the entire width (not only from inseam to outseam).
Front Rise
Measure the front rise from top of waistband to the crotch seam.
Back Rise
Measure the back rise from top of waistband to the crotch seam.
Inseam
Measure the inseam from crotch to bottom.