Planning Your Trip
Kayak is by far my most favorite booking engine!
I love the fare alerts option, and the fact that you can compare with other popular booking engines right at their website. You can also easily filter your flight results by airlines on their user-friendly interface.
If you have the luxury of flexible travel plans, use the Buzz feature on the app, which offers the best fares for a particular month.
Knowing When to Buy
Admit it...you HATE buying a plane ticket only to find out that the price went down the next day! Ok, so maybe you aren't as neurotic as I am (lucky you, it's a hard way to live).
Anyway, use Bing to check out fare predictions!
And although it must be nice to just be done with once you buy your tickets, I do want to add this little tidbit for crazy people like myself. A lot of major airlines allow you to hold your ticket or cancel it within 24 hours without a penalty if you DO find a better deal within that window of time! Nice.