Booking a cheap flight is a cheap thrill. You're delighted to think you have beaten the system and picked up a bargain. If it's really cheap, it may even have been the deciding factor in where you choose to travel.

But the reality is that, especially once taxes, charges and any fuel supplements are added on, genuinely cheap flights can be hard to track down. So use these tips to maximise your chances of finding the lowest fares.

Start by finding out which airlines fly to which city. Consult www.whichbudget.com for routes involving charter and budget airlines, and www.flycheapo.com for details of 50 budget airlines' routes across Europe. Other good planning sites are www.dohop.com, www.jetnav.co.uk, www.jumblefly.com and www.flightmapping.com.

Check for prices on some of the airlines' own websites. Search a few days either side of your chosen date in case the price drops. Tuesdays and Wednesdays usually see the cheapest prices for leisure travellers; Fridays and Sundays the most expensive. Sign up for email alerts so you can book tickets the minute they go on sale - particularly with budget airlines, this is when the lowest prices are on offer.

Consult a selection of online travel agents, too, as they may have different deals. Some of the best known are www.ebookers.co.uk, www.expedia.co.uk, www.lastminute.com and www.opodo.co.uk, but newcomers include www.lowcosthols.com and www.flexibletrips.com, part of Thomas Cook.

Another way to find low prices is to consult price comparison websites. These compare prices from a range of airlines and travel agents, but do not sell you the ticket - you click through to book. Some of the best known are www.cheapflights.co.uk, www.skyscanner.net, www.travelsupermarket.com and www.traveljungle.co.uk.

Charter airlines, such as Thomsonfly (www.thomsonfly.com), Thomas Cook Airlines (www.thomascook.com) or Excel (www.xl.com), which have lots of flights to popular summer and winter sun resorts, may offer low prices at the last minute. This is because their business model is different to that of the budget airlines such as Ryanair or easyJet, whose lowest prices are available when tickets first go on sale. Check the airlines' websites, and also those of online travel agents.

Factor in those extra costs. If that cheap flight leaves at 6am, you may have to pay for an airport hotel the night before. If it lands at midnight, will you need to take an expensive taxi home? And is it worth paying more for a direct flight to avoid the time and hassle of changing planes on a cheaper, indirect one?

Fed up with surfing the net? Consult a travel agent and get them to do the hard work for you. They have buying power, and access to fares you cannot find yourself. And if you are flying long-haul, or planning a complicated itinerary, it's almost always cheaper and easier to use an agent. Pop down the high street, or try some of these: Airline Network (0870 700 0543, www.airline-network.co.uk), STA Travel (0870 163 0026, www.statravel.co.uk), Trailfinders (0845 058 5858, www.trailfinders.com) or Travelbag (0800 082 5000, www.travelbag.co.uk).

Ensure the names you put on the booking form are in exactly the same format as the names on your passports.

Check if the airline website you are booking with adds travel insurance to the cost - some do automatically, but if you already have insurance you can uncheck this box. But wherever you buy it, I'd recommend that you always have travel insurance.

Read the small print about cancellation charges, or charges to change the name on the ticket or to swap to another flight - these can vary wildly, and sometimes such changes are not allowed.

Check to see if the company you are buying from holds an Air Travel Organiser's Licence (Atol) to protect your money. If it does not, it's still OK to book, but if the airline goes bust you probably won't get any help.

* Cath Urquhart is the author of a new consumer guide, The Times Holiday Handbook (Navigator Guides, £12.95), available for £11.50 and free p&p from The Times BooksFirst (0870 160 8080, www.booksfirst.co.uk).