Are you sitting comfortably at 35,000ft?

Rosanna de Lisle shares her 20-point survival plan for long-haul passengers

Bizarre as it now seems, jet travel was once considered glamorous. Now it is generally considered a huge pain ­ and with increasing awareness of deep vein thrombosis (DVT), poor air quality and proximity to hundreds of testy fellow travellers, we now know that it can be detrimental to the health as well as mind-numbingly dull. As a Londoner who now lives in Sydney, I have slogged through the 24-hour flight more than 10 times in two years. Here is how to survive the longest hauls of all:

Bizarre as it now seems, jet travel was once considered glamorous. Now it is generally considered a huge pain ­ and with increasing awareness of deep vein thrombosis (DVT), poor air quality and proximity to hundreds of testy fellow travellers, we now know that it can be detrimental to the health as well as mind-numbingly dull. As a Londoner who now lives in Sydney, I have slogged through the 24-hour flight more than 10 times in two years. Here is how to survive the longest hauls of all:

¿ Choose a flight which will get you to your destination in the late afternoon/early evening (study timetables on airline websites). Arriving around 6pm will give you a few hours to acclimatise, unravel your legs, soak in a restorative bath, have something real to eat and drink, and then flop into bed for an early night. This way you can have 10-12 hours' sleep and wake up in sync with the locals the next day.

¿ Choose an airline with a direct route and big seats and good "pitch", ie legroom. Yes, they do vary, even in economy. Also check how the airline configures the classes within the aircraft. Japan Air Lines, unusually, sometimes uses the upper deck of its jumbos for Economy, and it is a great place to sit: smallish, quiet (it does not put babies up there), well serviced (own galley and stewards) and, because of the curvature of the plane, the seats cannot abut the windows, so you get a locker which is fantastic for storing your hand-luggage (putting all your stuff within easy reach) and for parking your legs on.

¿ Wear comfortable clothes that you can get on and off easily. (Forget the Mile High Club; this is about acclimatising, not scoring.) For example, if you were boarding the plane in London in spring, you might wear light cotton trousers with two pairs of socks, a long-sleeved T-shirt and a fleece, which would peel down to trousers and a fresh T-shirt for landing in the heat of Sydney in late summer. In between, you will have been both chilled to the bone at 35,000 feet (planes are very draughty; don't think about why) and steamed like a dumpling while you touched down at Singapore.

¿ On aeroplanes feet swell to varying degrees, and there is a bit of a shoe debate among long-haulers. You can take your shoes off, but you may not get them back on, and will your fellow travellers thank you in the meantime? The trick, I have found, is to wear shoes that are slightly too big: that way your feet do not outgrow them. I have not tried the famous brown-paper-bag tip (by which brown paper put into the shoes is supposed to limit jetlag) and cannot see how it could possibly make any difference. Your boots have to be good for walking too ­ all those endless corridors. In other words, put the Manolos in the hold.

¿ Get the best possible seat you can at check-in, which will involve getting there early. Ask how full the plane is, and how to maximise your chances of an empty seat or two next to you. One spare seat gives you a bit of mental space and somewhere to park your mags; two changes everything ­ you can lie down. Often it is better to go for a central aisle seat than a window or a window aisle; the centre-centre seats are the worst of all, therefore fill last. If you have frequent-flyer points with the airline, say so and angle for an upgrade.

¿ Check that you are not being put near the toilet block (attracts crowds, emits increasingly nasty smells). The only people who can profit from being near the loo are the hugely tall, because they can stick their long legs out in that empty space by the emergency exit ­ the "bulkhead" seats, as they are known by frequent flyers. However, if you are that tall person, do not accept the window seat in this row: it is a complete con. Because the inner side of the emergency-exit door is fat and bulbous, it steals all the legroom that ought rightfully to belong to the window seat. I have seen a 6ft 6in rugby forward in that seat; it was a painful sight.

¿ Avoid seats that are side-on to the projection screen. You will have to crane your neck to see the one further up the plane, and you could be dangerously close to Baby Alley, the smallest passengers being affixed in bassinets to same wall as screen.

¿ Arm yourself with as much entertainment as your hand-luggage can hold. Go for variety: newspapers, mags, books both high- and low-brow. Don't read one kind of writing for more than two hours. Take a Walkman or Discman with at least five albums ­ it will save you from the tedium of the airline's uneasy listening looptape. If you do not have a personal stereo, wear earplugs to cut out the background noise. Watch a film if you want to see it, not because it can kill two hours.

¿ Take off your watch. Looking at it will only make you acutely aware of how long you've got to go, and if you realise that it's 3am at home and you have not yet had a wink of sleep, you will only feel more stressed about it.

¿ Pace yourself. Don't bolt meals (you have got all the time in the world ­ well, however many hours or days your flight takes). Resist the steward's attempts to give you coffee when you have only just peeled the foil off your main course.

¿ Indeed, resist the steward's attempts to give you coffee at all times. Up there it tastes awful and will only dehydrate you. Bring your own one-litre bottle of water; you can stash it in the pocket in front of you, sip whenever you want and avoid ending up with a pile of cracked plastic beakers.

¿ Drink alcohol if it helps you get off to sleep or, if sleepless and seriously bored ( tempus fugit when you have had a couple). But do remember to drink twice as much water or herbal tea. And don't expect wine to taste nice: it hates flying even more than you do.

¿ Take hand-luggage that can double as a footrest. The worst thing about economy seats is that people under about 5ft 8in end up with their knees lower than their hips, a nearly impossible position in which to fall asleep. A well-packed, load-bearing bag, eg a laptop, beneath the feet can help. Better still, fly with Singapore Airlines or BA, which has finally granted footrests to cattle class.

¿ Take a little pillow or a cushion. Airline seats have more hard angles and poky bits than you could hang your coat on, so all extra padding is useful. Even when you strike nirvana and get to stretch out on four spare seats in a row, the armrests and seatbelts contrive to ruin everything by sticking into you.

¿ Go to bed. Brush your teeth and take off your make-up before you try to go to sleep. Slap on the moisturiser. Take a mild sleeping pill (assuming they do not disagree with you): it might just stop you being woken by people knocking your seat, talking loudly in your ear, or parking a chicken breast in front of your nose. But do not put yourself out for the count.

¿ If you find you cannot sleep, don't flap. Just appreciate the time to do nothing but read/watch a movie/write letters ­ the kind of time you never seem to get at home.

¿ Remember to get up every hour or so to stretch your legs. And really stretch them, as you would at the gym. Use any stopover to get some exercise, even if it is only pushing a trolley around duty free. Jog up and down some corridors and then lie down in the departure lounge to ease out your crumpled spine. You may feel silly, but it is all useful preventive stuff against DVT. As is aspirin, so they say.

¿ Don't overeat, but equally do not worry unduly about the airline grub. Unless you have come onboard, wallpaper* magazine-style, with your own lunchbox of sushi and Vietnamese rolls, you haven't got many options. And when you have been stuck in the air for 10-hours but-you-could-swear it's-been-36-already, the arrival of a poached pork sausage, vinyl omelette, and Viennese whirl is an event not to be sniffed at.

¿ Try, roughly, to keep pace with the sun. The stewards like to keep everyone in darkness between meals, presumably to encourage us to nod off and not bother them, but if it is light outside and it feels like daytime to you, open your shutter. It might be the only time you get to see Siberia or the South Pacific.

¿ Persuade someone to meet you at the airport. You will perk up when you see them, click into local life and forget about the nightmare experience that only hours ago you seriously thought would never, ever end. You need this kind of total amnesia: it is the only thing that will ever persuade you to take another long-haul flight again.