2. Travel off-peak. Just like taking the train, flying off-peak (generally late-morning to mid-afternoon) will be much cheaper than other times of day.
3. Book as far in advance as possible. Generally airlines release seats at a lower price and then gradually increase fares as the plane fills up. This rule especially applies on popular routes. If ticket sales are slow prices will go down in a bid to put bums on seats. Last minute bargains can be found, but this is high risk strategy unless you are very flexible.
4. Don't be conned by the headline price you see in no-frills airline adverts. No-frills airlines have become notorious for adding extra charges to the basic price of your flight ticket. The price you see in the glossy adverts is virtually never what you will actually end up paying.
5. Flights are often cheaper if your stay includes a Saturday night when travelling with a traditional airline (BA, Lufthansa, KLM etc). These airlines make most of their money from business travellers who generally only fly on weekdays, so their pricing structure is adjusted accordingly for leisure travellers willing to stay over a weekend.
6. Be brave and fly to one of Ryanair's secondary airports. The no-frills airline pioneered using converted airfields (field being the operative word!) as a way of cutting down costs. Extreme examples like Frankfurt Hahn are practically in another country to the city they claim to serve (Frankfurt is 74 miles away from Hahn airport). Big savings are possible if you don't mind a lengthy journey to your eventual destination. Just don't forget to factor in the cost of getting to and from the airport.
7. Fly to destinations where competition keeps prices down. The cheapest flights are usually found on routes where multiple airlines are vying for your custom. Manchester to Alicante (five airlines), London Gatwick to Malaga (four airlines) and London Heathrow to New York (six airlines flying to either JFK or Newark) are prime examples of this.
8. Be realistic about how cheap a flight will be to off the beaten track destinations. Don't expect to find a cheap flight to the likes of Nepal or Fiji which have no direct flights from Europe.
9. Be prepared to take connecting flights rather than going direct. Connecting flights can sometimes provide the cheapest option, especially if you are travelling long-haul and are prepared to add at least a couple of hours to your journey time.
10. Use flight price calendars provided by sites like Skyscanner to compare fares across a whole month.