One option is to sign up for email alerts of travel deals, this way you are notified of flight deals for your area. Another alternative is to use a search program that allows you to search for multiple airlines at one time.
Book your tickets as soon as the airline opens them up. Then watch the fares closely, most major airlines will refund the difference if the price goes down.
You can check on Orbitz or Travelocity. Another way is to try to travel by standby. There will not always be seats available for the tickets you may want though.
You must choose a low-cost airplane company like WizzAir, BlueAir and choose the lowest price to your destination. Reserve and pay with credit card or you pay when you take the tickets.