I love this consumerist post on tips to stay broke.
Using financial software like MS Money or Quicken is very important IMO. If you know exactly what you have, where it is, and where it is going there's a feedback loop from your activities. How much do you spend on bills? How often do you use that landline vs. your cell phone, and how much does it cost? Can you just get rid of it?
Having real solid numbers, being able to track where money is coming from and going to, these are the things that allow our brains to do what they do best: find patterns. Once you understand the patterns of your financial life you can make good decisions.
The patterns people find from positions of ignorance seem to lead more often to bad decisions, reflected in that list.