CORPORATIONS
Incorporate every production over $5,000! Because they're out there, lying awake, thinking about how they can sue you or take over your production. The corporation is your best way of keeping the flakes and the leaches off your back. I know, you're saying, "This guy's paranoid." But you'd better be a little paranoid in this business. You'd be surprised how many people prey on talent for their living.
You also need the corporation for taxes and other legal matters when dealing with distributors, lawyers and all kinds of contracts and business affairs of film making.
One good practice is to incorporate every production as a separate entity. That way when you sell the production to a major or independent distributor, if you opt to go that way, especially if the bucks are there, then you can close down the corporation and eliminate a lot of vestigial liabilities, such as some actor waking up one fine day, two years later, and saying, "I think I twisted my neck when I kissed that hydra! Didn't they have liability insurance on that picture?"