Focus, focus, focus!
One movie at a time: from investment, production, exhibition, to net profit.
Build your network.
Filmmaking is, sadly, a collaborative medium. A little cult around you helps keep costs low.
Whenever you profit from your movie, reinvest it into your filmmaking enterprise.
Hire slowly, but hire well.
You can't do everything in a movie and do it well. Hire out most roles so you can focus.
If you hit a nerve in culture, and begin to profit immensely, replicate what you're doing.
(Think: Soderbergh's sexy action-thriller movies.)
Cut emotional attachment and be honest with yourself.
If you're not where you want to be, look in the mirror and ask yourself why.