I'm really surprised at how many people don't know the tricks of the airline industry. The know people are at work surfing the net for vacation plans and jack up prices during work hours. Also people have time to surf over the weeked so prices are high then too. I always find luck on Wednesday or Thursday nights. And I never buy the first flight I find unless it is such an awesome deal I'd kick myself if I didn't. This has happened exactly once for me.
So here are some helpful tips:
1. Check multiple times in the day
2. Try to look on Wednesday or Thursday evenings.
3. Get signed up for deal alerts from your favorite carriers. For me it is Delta and Southwest.
4. If you have time or are a night owl looking at the website shortly after midnight on Wednesday because this is when all the unbooked reservations.
5. First isn't always best. If you are willing to risk it you can find cheaper flights as the date gets closer and the airline is trying to fill the plane. My friend Kathryn is a master at this.