Spend about 30 minutes drawing one of your own hands. Draw from live observation, not from a photo. Proportions should be accurate, and you should have time within 30 minutes to add some shading in your choice of style. Your hand should be in a dynamic, interesting position, not flat and spread out. Oh, and your hand gesture should be rated PG. Don't throw a gang sign, don't give me the middle finger. :)
Tip: Use the knuckles and fingertips to look for drop lines and cross lines to maintain accurate proportions.
Here are some examples. Note that these are not photorealistic -- they look like they were drawn rather quickly, but the proportions are accurate.
