I also look closely at the eyelid for any contact or flatness. Some soft strikes or die weakness makes it very hard to get always right.
Look at the 58 LD or the 84 5 cent pieces as the toughest to grade properly.... next to impossible to get right without examining them in hand.. Weak strikes ..die wear ..these dates have both of these problems..
So a weak center or die wear can still be hiding a nice ch unc in there..and often seen in the 58's and 84's..5 cent pieces.
I also look at the hair around the ear in the young vickies..because often these will still be missing detail and can fool you into lowering the grade..