I have no background in Latin and am probably doing it all wrong, but I'll tell you what I do anyway. :D For translation exercises, I count each sentence (Latin to English, English to Latin, doesn't matter) as five points. I don't know enough Latin to pick apart every little bit of a sentence, so I've just been taking off two points for mistakes involving the simple subject or predicate and one point for any other mistake within the sentence. An example:
Translate the following sentence into Latin:
Christ was killed that men be saved from death and sin.
Christus interfectus est ut homines e morte et peccato eperentur.
"Eperentur" should be "eriperentur," so I took off one point.
For straight vocabulary questions, one word equals one point.
Each declension chart-type question (decline "mensa, mensae") is worth five points.
Each conjugation chart-type question (give the present indicative of "exeo, exire") is worth three points.
Waiting for Ester Maria's reply! :bigear: