1) General J.E.B. Stuart wasn't there, and he was an asset to the Confederate army.
2) The Confederates brought on a "general engagement" too soon
3) The Confederates should have taken the defensive on the second day
4) The wrong point of attack was taken on the second day
5) Longstreet delayed his attack on the second day
6) There was uncoordinated and poor artillery structure on the third day
7) The point selected for Pickett's charge was badly chosen
8) Pickett's charge was not properly supported
9) A lack of well trained staff officers caused failure