boy do i! i draw the icon at whatever size (usually 800x800) then paste the entire layer-flattened thing into a 100x100 canvas and ctrl-T until it looks like a good crop. it's just awful when you resize the entire canvas to icon size, unless you've got a crazy good eye for this stuff you will always have a bad crop.

i also usually use a circular gradient quick mask begun at where ever the light source would be, inverse the selection, ctrl-J to duplicate it, and set that new layer on color dodge or color dodge (add) at about 60% opacity or whatever looks best. it helps faces stand out. but don't make it TOO strong or you run the risk of recreating that god-awful trend from a couple years back of having white floating blobs on your icons. (also let me know if that was too photoshop-jargon for you, i'm not sure what level of expertise you're at, and i can simply that if needed)