"...a good beginning must make the audience feel that it doesn't know nearly enough yet, and at the same time make sure that it doesn't know too little"
Why? If the audience knows too little, then they won't have any interest in the film; but if the audience are fed the information slowly, building up the tension of finding out how the plot will unfold, then they will be eager to carry on watching.
Critic Stanley Kauffmann described what was once called 'the classic opening' - 'a film began with an establishing shot of New York City ... then the camera went up a building ... then it went in the window, then it went past the receptionist desk to the private office and there sat Cary Grant'. What he means by this is the fact that once film openings would always tell its audience where the film was taking place, the occupation of the character, etc. where everything was what was expected.
The title sequence by Kyle Cooper for the film Se7en is one that is well-known; it is unsettling but exciting, and so effective because it wakes everyone up and feels like it is part of the film. Another opening is that of Orson Welles' A Touch of Evil. Welles originally wanted no titles or score over the opening, but Universal Studios disagreed. Needless to say, Welles wasn't pleased (to the point of his writing a 58-page memo to the head of production); he wanted to plunge the viewer straight into the plot, without unnecessary distractions.
A favourite trick of film noir, as observed in the 1995 film 'Casino', is to begin a film with the ending. The result is a film comprising of flashback(s) leading up to the events shown at the start. Arguably, it is an effective technique; if done right the viewer will be left wanting to know what happened in the lead-up to that scene.
"...it's also a quality many great beginnings share, they feel like a destination as much as a departure point, looking ahead to what is to come"