These are some good clues.
I will add only one more, which is a theory put forth by my wife years ago. If you see a forthcoming movie advertised heavily on television, it's likely to be a crappy movie. Movie companies focus test movies before they're released, and if a movie tested poorly the company wants to salvage as much as it can can (can you say "sunk cost") before people find out the truth about it. Therefore, by advertising heavily, the company seeks to generate buzz that will cause people to go to see the movie during the opening week, after which the truth is out and people quit seeing it. (Note: All the funny scenes are in the ad.)