If you tend to book through your travel agent thinking that he or she will find you the cheapest deal, think again. They are paid to do a job and it is true that they do a reasonably good one, but most of them will not go out of their way or go that extra mile to make sure that you have the cheapest and most convenient flight.
The answer is that much of the time, you are best to do it yourself on the internet, through one of the cheap travel sites such as flights world This way you can examine all the options to make sure that you have the best deal going.
You can try different dates to see if the price goes down, which is a great way to save money if you can be a little flexible on your dates.
Even shifting the trip by one or two days, or even taking a different flight on the same day can make a real difference.
While some of the travel agents only look at the most well known airlines, you can save quite a lot of money if you take one of the lesser known airlines, especially if you are willing to stop off en route. You can save hundreds of pounds by taking a non-direct flight on the long haul services.