Here is a list of things not to do.

First: don't assume the actors will turn up, especially if they don't have some number where they can reach you.
Second: don't make the place you're filming, even if only for a few moments, look like Beirut in the middle of a war; people will complain you're not being realistic, in other words they're offended that your cold cynical eye has filmed their beautiful town and decided to concentrate, albeit only briefly, on the Mean Streets (or, in Kastoria's case, the Mean Street).
Third: Don't show the 'rushes' to the actors.
Fourth: Your talented foreign cast have difficulty enough with exact intonation in English; don't expect their acting to be anything else than ham; be surprised when they underplay, in true film style.
Fifth: Don't have two female students fancying the same man, or two male students fancying the same woman.
Sixth: Don't trust people who say they are trying to organise a theatre festival, and will be able to find a couple of actors for you; only trust them if they are actually organising a theatre festival.
Seventh: Under no circumstances appear in the film yourself; you'll be caught up in the general hammery and end up sounding like an Anglo-Greek with an unplaceable accent and a lot of strange wild tics.
Eighth: don't allow people to change lines.

AND HERE ARE SOME DO'S:

First: Do make sure that the actors involved are not likely to suffer from heartbreak in the near future, or have relatives that are close to death's door.
Second: make sure your students don't know anything about the script except the part they appear in, and a vague outline of the story.
Third: when shooting running sequences, make sure the actors really run.
Fourth: avoid filming near mosquitoes and other biting insects, or be stoical.
Fifth: make sure the married women take their wedding rings off when they're supposed to be playing single women.
Sixth: Make sure that children not partaking are as far as is humanly possible away from the camera or the microphones.