If you say you're going to do something, do it! When you fail to keep a promise, it tells others that you don't value their time or relationship. Don't over-promise; under-promise and over-deliver on everything you do. And a few words to the wise. Never make a big decision when you're angry, and never make a big promise when you're overjoyed.
I think this is really smart for every woman. Know yourself. Know what works and what doesn't, first. You might think you know, but you will never know yourself until you spend a significant amount of time on your own. It's a great, big, fun, world out there!