You need to go beyond event countings at times when not all wrong answers can be eliminated that way. BY interpreting the solid and hidden lines given and determining where certain structure (depression, protrusion, ...) locate, it will confidently land you on the right answer.
Great 2D and 3D illustrations come along with DAT Achiever. You should consider using it. It's an awesome guide to further help visualize angles/edges/... alot more completely.