When I got my ticket, I had a general range of dates I wanted to travel. I wanted to leave sometime before the Christmas rush to beat the price hike and return sometime in January. Make sure when you travel to allow 3-4 days before and after major Holidays to buy tickets and it's always a plus to be flexible with your dates.
When it comes to finding the cheapest ticket, check all the travel websites first, like Kayak, Travelocity, Orbitz, StudentAirfare, Hotwire and so on. Begin to do some more research now that you have a base price and range.
Check airline websites directly, bypassing the bulk sellers of tickets, sometimes you can save a couple hundred dollars by going directly to United Airlines website for example. Ultimately I found the cheapest airfare through a travel agent, booking the flight for $630 round trip, total.
I flew Chicago to San Francisco to Osaka, previously I've flown direct O'Hare to Tokyo for around the same price.
To make some extra cash while traveling, when you get to the airport, go to the gate and ask the attendant how well sold the plane is. Airlines typically overbook 5% or so depending on flight. Put yourself on a list for overbooking, so if the flight is overbooked you give up your seat for someone else, get a couple hundred dollars in cash, a night in a nearby hotel and usually fly out the next morning. You can't beat this, if you do it on the way there and back you can pocket some extra cash, sometimes up to $200 each way.
One last tip, when searching for a flight avoid the summertime, it's always busier, pricier, and slower. Fly in downtimes and check for flights with crazy layovers. I saw flights to Tokyo that had a 20 hour layover in Rome. This may not be for everyone but you get a cheaper flight and enough time to run around Rome for a day.
View the rest of this series on my $2000 trip to Japan, with tips of lodging, travel packing and eating.
Safe Travels.