In the audition, make them read the scene a lot of different ways to see if they actually take direction. It's tough because you typically have a lot of people to get through, but don't rush it. Also, trust your instincts! if something doesn't feel right, even if it's just a little something, re-evaluate.
We had contracts, but once you start rolling on a feature and your lead actor implodes at the starts of week 2 and all your money is spent on equipment, it didn't really matter.
My #1 goal was to make sure he didn't just quit the project so I still had something to edit.
Editing, by the way, took a full year due to performance issues, including having to re-write the movie in post. But the finished product, i feel, is something I'm very proud of.