While there's no real shortcut to finding cheap airfare, if you're willing to put in a little time and effort, you could save big on your next flight. Here are nine tips to help you save money on your next vacation.

• Set up daily or weekly price alerts will help you know when prices drop so you can get the best deal.

• If you're flying within the U.S. or to select international destinations, Bing Travel (Bing.com/travel) can help, offering fare predictions for most major cities. Just plug in your itinerary and the site will advise you either to book now or to wait, depending on whether the fare is expected to rise or drop. Another useful site is Kayak.com, which offers fare history graphs for domestic and international flights.

• Prices are at their lowest between 18 to 28 days prior to your trip and is the optimum time to book. Domestic fares are lowest 21 days before departure. The average fare increases 5% two weeks before departure, with fares increasing 30% from their lows the week before departure. International fares don't fluctuate as much. 34 days before departure, fares are about 4% lower than the average at six months before departure.

• By booking a package deal (hotel and airfare) with an OTA, people can save an average of $525 on their vacation, with an average of $1,000 saved for weeklong vacations to popular destinations.

• Airlines announce their sales on Tuesdays. Mid-day Tuesday to late-day Tuesday or early Wednesday is a good 24-hour sweet spot where you can find the latest sales.

• Wednesday is the best day to depart, followed by Tuesday and Saturday. Experts cite savings of up to 10% when traveling midweek to midweek. For weekend trips, you'll find that airfare is cheapest when you depart on Saturday and return on Monday.

• Overnight flights can be good bargains, as well as late afternoon or dinner flights. Initially, when you're doing your search, don't specify departure times. This way, you'll be able to see the time of day that really is the cheapest to fly.

• A one-stop flight in a city that's a hub for the airline can generate some dramatic savings and lower fares. When traveling with small children, time during a layover may be a welcome break from the plane.

• Buying two one-way tickets from different airlines may be cheaper than a round-trip ticket. Try  Kayak's "Hacker Fares", which pairs up one-way flights from different airlines to create a discounted roundtrip