I have not missed a payment for 6 years, and in that time I have PIF almost everything every month. I have carried a balance over about once a year on average, and not for more than a month. Over that period I have paid more finance charges for using cards overseas than I have for having a balance.
For 5 years that did very, very little to improve my scores. Last December I was pre-qualified for a new mortgage and saw the CRAs comments on my scores and decided to do something about it. I caught on to all the tricks, and became very disputatious with everything, applied for credit I didn't want, made my wife an AU, ensured that I had small balances reporting by paying twice a month, cleaned up everything that was cleanable (except EX ). I learned who made hard pulls when (and grew to hate Cingular), became very careful about the things that matter to FICO.
For me, step one was to live within my means using anything possible (think long term, not short term). Then I had to learn time was my friend. What took the longest to learn was that PART of having a good score is a game. Being fiscally responsible is necessary but not sufficient (any mathematicians out there? ). To really improve your score you have to follow their rules, which can be irritating, but really does not have a deleterious effect on your life.
Finally, I logged on here to finish up my education and have fun