Things you need will be a measure tape and a friend to help you. It is easier and more precisely if somebody else takes your measurements then your self, because you should stand straight and not move around!
The most important thing about a measurement chart is that you can read it and it got all measurements, also for your future reference.
(You should always make sure if you want something to be custom made from a latex manufacturer that you are accurate with the measurement drawings they provide to you.)
TIP 1. The to be measured person shouldn’t be wearing more than underwear while taking measurements, to get exact results.
TIP 2. Take a ribbon or something similar, which you can bind around the waist. This is one of the anchor points where you´ll have to refer to the most of the time. (Makes it easier for you to find that point again!)
TIP 3. While taking measurements the measure tape should not hang loose around, but don’t pull to hard, just because latex is stretchable it doesn’t mean that you should tighten the measure tape as much as possible.
Some examples for taking the measurements:
Measurements for the hip should actually be taken at the point where your hip bones are (you will be able to feel them, two bones to the left and right), but in a lot of the cases you will see on measurement charts that they take the hip measurements a little further down. In that case they actually ask for the widest point. No problem! Just take the measure tape a little further down, so that you also get your bum in there.