Everyone's second Chess Book

NM Dan Heisman

He has a list of the 10 most common mistakes for those in the 1200-1600 range

** Not think about the opponent's moves...and being overly focussed on one's own attack
** Being in awe of the opponent
** Attacking before all the pieces are in play
** Falling for an opening trap
** Moving too fast. (He actually recommends sitting on your hand to resist this reaction)
** Not being good at "counting" (not sure if this was a mistake)