Torso length:
Start at the C7 vertebra at the base of your neck. The best way to find this is to bend your neck and feel the first bump along the base of your neck. This bump is where you will want to start your measurement. 

Next, you'll want to find the midpoint between your iliac crest. To find your iliac crest, cup your hipbones on both sides and find the center point on your spine. This midpoint is where your thumbs should be pointing. 

Finally, you'll need help measuring from the C7 vertebra to your iliac crest. From there, you'll have your torso measurement.