My friends ask me all the time what are my secrets to finding the really cheap flights, as they know that I like to travel and that I was not born with a silver spoon in my mouth, as The Who sang so eloquently. Ben Franklin had it right when he said a penny saved is a penny earned.
The biggest secret to finding discount airfares is look in allot of places and start looking early! AND not all of the places that you should be looking at are on the internet! I have looked up deals on the internet and then went with the information to a travel agent and see if they can beat it, and sometimes they can, as they get spiffs from the airlines, or the airlines are special promoting a destination to the travel agents, and they can pass the savings on to you, if you ask. For instance, China Airlines ran an age special for the travel agents and they would give you your age off the fare, normally the travel agents would have kept it but they had to beat the internet flight deal to get me to buy the ticket so we both won. While you are there ask them do you have a really cheap flights coming up that I might be interested in again they can surprise you!
Another place to look is in your local paper, lots of times travel agents will buy allot of tickets to a place in a block and then resell them; as the block gets close to expiration, they have to discount what they have left otherwise they lose all the money on the tickets that they have bought but haven't sold. The travel agents will often use them in packages that they put together, so when you buy them they will push certain hotels, sometimes if you need a hotel with the flight you might get a really cheap hotel room that is a couple of stars higher than you would normally stay at the price you would normally pay, so you don't save direct but you get better value and spend the same as you would have otherwise.
Crazy but true I always look at the travel agents windows when I pass them, you might see a last minute LA to London special for $499 promotion, who knows why it is that cheap, but being open to those kinds of deals can be allot of fun, and give you something to do on the spur of the moment.