It is a good idea to prepare for your trip ahead of time.
Did you know that the closer you are to your departure
day the more you will most likely have to pay?  

Sometimes being flexible can result in dramatically lower
fares. So next time you search on DestinationCompare.com,
select the flexible dates option. You may find out that  flying
Saturday is cheaper (though not so much for international).
Likewise, traveling mid-week (Tuesday or Wednesday) is usually
cheaper than Monday or Thursday/Friday.

Slow times are good times to save.  The slow times will vary
by route (early morning and late night are good for leisure routes,
mid-day is usually best for business routes).

Do the unexpected. Try not to travel when everyone else is.
Go to Disneyland or Las Vegas after Thanksgiving and before
Christmas.  Not only will the flights be cheaper but the lines
may be shorter.