A You can do a flight search online by visiting discount ticket sites one at a time, or by using a flight search service site like sidestep. You really have to pay attention to what comes up though, as sometimes savings are not worth what they might seem. If you cannot choose your own days, and you cannot be flexible about when you leave, a cheaper ticket is not going to do you much good. However, if you find something in your flight search a day after you wanted to leave, and you can swing that, you have just found a deal.
One factor to consider is the number of stopovers for a flight when searching for airline ticket deals. There are times when a flight is one way with one stop, or no stops, but a less expensive version might stop in three different cities along the way. Most do not like that many stopovers because they feel that ups the chances of lost luggage and takes too long. However, if you do not mind that too much, and you find a cheaper ticket through a flight search with many stops, take it if the savings seem to be worth the extra hassle.
When you search for flights, it depends on when you do it. The results can vary tremendously. Looking for flights as early as possible is going to bring up the cheapest air travel deals for you to select from. If you wait until a week before you have to go, your flight search is going to yield very few deals. It also depends on the day of the week you choose to search. Some say that Wednesday night is when many cheaper flight seats open up, so you may want to look then, or first thing on Thursday morning to see what type of deals you can find. You may save fifty dollars by searching, or you may save two hundred and fifty. You will not know until you look.