The width of the hand is taken at the knuckles. We usually have the hand relaxed on a piece of paper and trace the hand. Check the angle of the marking instrument. You want the exact width of the hand. If you hold the pencil vertical, the measurement will be too large. If you angle the pencil and push in as you mark the measurement will be too small. You must have the exact size of the flat, relaxed hand. The width is the most critical measurement. 

The length is from the web between the fingers to the end of the longest finger. The concerns of overlength and underlength as described above are important.

Scanning the hand with a ruler to the side has been very successful in obtaing the necessary measurements. Then email the scan to us. A "xerox" copy faxed has worked but often is not as clear.