- PRIVACY: put the grade on the *second* page, so that it is not visible

- SIGNING: put your initials, so that people know whom to contact,
  if they want a regrade

- EXPLANATIONS: no need to give the solution - we'll publish them -
  but clearly mark the penalty/score, and mark the reason of your score
  I suggest you put 'check-marks', whenever the answer is correct.

- CONSISTENCY: write down the list of rules and penalties,
   for partial credit, for consistency.
   Eg., "missed the referential IC from 'gym' to 'customer': [-1]"

- DUE DATE: let's have the grades ready by Monday night,
   so that we return homeworks on Tue

- SORT questions by student last name