If you can be flexible about when you fly, you might score some good savings on your ticket. There are certain days, weeks, months and times of day that offer cheaper fares.
Wednesday, Tuesday and Saturday are the cheapest days to fly. Friday and Sunday are the most expensive. Tuesday afternoons through Thursday are good days to find sales on destinations. If you want the absolute cheapest fare, book your ticket for the red-eye flights or the earliest morning flight scheduled. Flights scheduled during lunch and dinner hours also tend to cost less.
The first half of January is a good time to buy tickets. Airlines run destination sales then, and available travel dates usually extend into spring. Fares are highest for peak travel seasons like summer, Thanksgiving and Christmas.