Jessica, good tips. I especially find Tip #1 has helped me quite a bit. A small notebook is with me almost anywhere I go.
Two additional tips that feed off of your idea:
1) If you are on the keyboard quite a bit, I encourage you to explore a web tool called Evernote.com. At it's most basic, it serves as an online notebook, but with the advantages of cut & paste, and hyperlinks. You can also add the notes from your notebook so that all of your ideas and references are in one place. Evernote also has apps for iPhone, Blackberry, iPad, etc. for even easier access.
2) Dragon Naturally Speaking is a program that converts speech to text. I am in my car frequently, and when ideas come to mind I can record my thoughts on a small digital recorder (I recommend Olympus) with a USB connector. When I get back to my office I plug the recorder into my PC and my thoughts and ideas are converted to text by Dragon. With a bit of cleanup, I then save the text in - you guessed it - Evernote for future use.
I would love to hear your thoughts and the suggestions of other Biznik'rs on how they capture those brilliant moments and ideas for use in future blog posts.