This article from The New York Times is probably the best I’ve read about booking tickets online. To summarize, here are the steps for ensuring you find the best prices no matter where you are flying:

1. First check kayak (my personal favorite as well)
2. Next check ita software
3. Cfares – this website costs an annual fee of $50 but they offer rebates on every flight you booked so it might be worth it if you fly a lot or find a competitive price
4. Lastly, go direct to the airline you are planning to book with.

If you have some time, you might want to check farecast.com or yapta.com to see if these websites might predict the price going down anytime soon.

For international flights, he pretty much follows the same process but also checks a website called vayama

And don’t forget to fly tuesdays or wednesday when tickets are usually the cheapest.

Read the whole article here.