Here is a tip I learned while trying to juggle several gmail accounts: make sure you get in the habit of signing OUT of the different applications and accounts. Case in point - this was why several of you were not able to create your blog the first go around - Blogger wanted to use your personal gmail/google accounts since you were still signed in on those accounts. Just a royal pain in the you-know-what. SO...sign-off or out every time you leave those applications. This counts for your cell phones, too!
Also, in reference to Google Docs and security... please pay special attention to those "share" options. Some of them will throw your document out on the web for the whole world (literally) to see. And....that just might not be cool with you.