It's OK to get problems wrong as long as you learn from them. Examine each problem and see what went wrong in each one. Essentially, the keyhole section comes down to this strategy:
-Look at the first answer choice
-Try to figure out which side the answer choice matches up with to the original shape (top, front, right end, back, bottom, or left end).
-Go feature by feature, piece by piece, in the answer choice and match it up with the original shape. If there is an inconsistency, eliminate the answer choice.
-Rinse and repeat until you only have one answer choice left.