If you are the kind of person who meticulously sorts and organizes your Gmail, applies labels consistently and insightfully, and efficiently deletes superfluous emails, then this post is not for you.
However, if you're more like me, and you just archive everything to get it out of your inbox, then this may save you a lot of time and energy.
If you're trying to find an old email, and you type a search term in to Gmail's search field (at the top of your inbox), Gmail spews back thousands of hits -- anything that contains the text in any possible field.
However, there's a way to avoid all that trouble: use Google's search operators.