They used to be called packaged tours, which conjured up an image of coach-loads of tourists thinking: 'If it's Tuesday this must be Belgium'. Rebranded as escorted journeys, these off-the-peg and tailor-made holidays cover almost every country on the planet, and certainly all those for which a tourist visa is obtainable. Not only are there hundreds of places to choose from, but dozens of ways to enjoy them, from museum tours to pottery workshops or, for the energetic, from kayaking to trekking or mountain biking. There is something for everyone, whatever their age, whatever their interests and whatever - let's be honest - their suitability for adventure travel. The moment of truth comes at the airport check-in counter or departure lounge, where passengers cast covert glances at the luggage tags of their fellow travellers, with hearts lifting or sinking as they recognise those who are on the same tour. It is no exaggeration to say that a trip can be made or destroyed by the people on it and, on a fixed-departure trip, there is nothing you can do about it. There is always the risk of encountering a nutter seeking a soul mate. And the more exotic the destination, the more likely it is to attract 'trophy hunters' who are more interested in bagging another country than they are in discovering the enjoyment it has to offer. It is not surprising, therefore, that more and more people are opting for the more expensive but less risky tailor- made tour, which is put together just for them, whether 'they' are a couple or a group of friends.

Although there are fewer risks inherent in a tailor-made trip there are still ways of ensuring that it goes smoothly. Couples will be fine - the problems arise when a group of friends and acquaintances get together for exotic travels. Bear in mind that people with whom you get on well at home may be disastrous travel companions and, since you are friends, you cannot simply ignore them. Remember, too, that many people who have only travelled in Europe and the Western world will be unprepared for the rigours of the developing countries. They may take it in their stride or they may spoil the enjoyment of the rest of the group with non-stop complaining. They will need someone to complain to, so one member of the group must take on the role of leader.

Apart from being willing to listen to grumbles, he/she should be an experienced traveller who will know what questions to ask the travel agent or tour operator before departure - such as, is there a danger of being combined with another group for certain tours? The risk here is that you could be put with a larger, non-English-speaking party. The leader should also consider the problems of smokers versus anti-smokers and decide on rules that suit both parties.

A compromise between a tailor-made tour and a fixed-departure trip is to get your own group together, decide on your preferred travel dates, and negotiate with a tour operator for a discount on one of their standard itineraries. With your agreement he can add some more clients to make up the numbers.

Whether tailor-made or fixed-departure, how do you choose the perfect holiday? First take a long hard look at... not the holiday brochures, but yourself. One of the paradoxes of travel in the developing world - and I am assuming that most readers of the Traveller's Handbook will be venturing to the more unusual destinations - is that the type of person who can afford the trip is often the type least suited to cope with a very different culture. In the West a strong sense of right and wrong, assertiveness and organisational skills are the personality traits that lead to success in business, and thus the income to finance exotic travel. But these 'A-type' personalities often find the developing world unbearably 'inefficient' and frustrating. By having control over their itinerary through a tailor-made tour, such people are more likely to get the most out of their trip with the minimum of frustration. A group tour, where they must 'go with the flow', may be the least successful option. Conversely, the happiest group travellers are often those who can adopt the attitude of one elderly woman, who announced to her tour leader: "I'm going to give up thinking; it doesn't work in Madagascar". It doesn't, and she had a great time!

If asked to pick out the two main reasons to choose an escorted tour over a tailor- made itinerary, I would say friendship and knowledge. When a group really jells the holiday will be remembered for all time, and reunions will take place each year because these new friends can't bear to let go after a fortnight of shared laughter and awe, when the lows become highs because of the feeling of camaraderie. Several of my close friends are people I met on group trips up to 20 years ago. Fixed-departure tours are an excellent choice for single people, who should be advised that the inevitable singles supplement is usually preferable to the risks of sharing with a stranger.

The knowledge part of the equation comes with the expert leaders provided by the best tour operators. A truly great leader is able to share his or her knowledge of the country in an enthralling way, so that no one is bored and no one feels diminished because their level of knowledge or interest is less than that of the others. Your leader should be an extrovert and a raconteur, as well as a smoother of ruffled feathers and a diplomat able to deal calmly with the trickiest situation. Such paragons are hard to find but they do exist. Personal recommendation is invaluable here.

After that long, hard look at yourself you need to take a long, hard look at your bank statement and promise yourself you'll spend as much as you can afford. If you are planning to go somewhere genuinely exotic, try not to be influenced by price or name. What matters is not saving the odd £100, but the itinerary and the leader, particularly in special-interest groups. Be wise to the false glamour of a posh name - once you arrive at your destination your holiday arrangements are likely to be in the hands of a ground operator who provides the same service to all their overseas partners, big and small.

Before you even start looking at brochures, buy a good guidebook and get a feeling for the country of your choice and the places you would most like to see. Then send for AITO's Holiday Directory. The Association of Independent Tour Operators has around 160 members, who are all extremely knowledgeable in their own specialised area. With the directory it is easy to see which tour operators cover the region or country you are interested in, and the activity that you find most appealing. Call 020 8744 3187 for a copy of the latest directory.

Magazines are the best source of information on tour operators offering special- interest trips. If you are looking for a riding holiday buy a horse magazine, if it's painting you are after look in an art magazine, and so on.

Travel shows such as the Daily Telegraph Adventure Travel Show and Destinations in London and the Independent Travellers' World in other parts of the UK give you the chance to meet and talk to tour operators as well as find inspiration. By the time you are ready to make a choice you will be well informed enough to pick out the tour operators who do not know the country they are selling (yes, it happens!). If place names are wrongly spelled or animal species incorrectly named you should be wary of travelling with that company. Much better to choose a specialist with a proven track record.

Don't hesitate to ask for the contact details of people who have been on the trip you are interested in. A successful tour operator will have no qualms about putting you in touch with former clients. If you enjoy your trip you can volunteer to be a referee for that company afterwards. It is also helpful to talk to the trip leader beforehand and to some of the other people who have signed up.

If you have an independent travel agent whom you trust and have worked with before, let them do the leg work - it will cost you no more. They will save you lots of time and can help sort out any serious problems that arise while you are away.

Here's a little story to close this section. Once upon a time in Bolivia a group of Americans assembled to enjoy a trek over the Andes and into the jungle. The first obstacle to holiday bliss was evident immediately: the party was made up of 11 women and one man. The next obstacle emerged a few hours later: the women were divided into two groups, one of which had signed up because they were ardent feminists and would only consider a trip that had a woman leader; the others were hoping to meet the man of their dreams. The one man was oblivious to both - he was a cocaine addict who was fully occupied by his quest for coca leaves. None of the 12 travellers was particularly interested in trekking.

The guide, Jean-Paul, was a Frenchman who looked like Rudolf Nureyev. He was a poet and a mountaineer, had romantically flared nostrils and a temper to match. One of his first comments was that he hated women and Americans.

Highlights, or rather lowlights, of the next six days included the news, on a village radio, of an attempted coup in La Paz ("Tanks and dead bodies all over the place," said Jean-Paul dramatically, but not entirely accurately), food-free days because the muleteers had sold our provisions to villagers along the way to make up for their lack of wages, part of the group becoming separated from the others and sleeping on the floor of a village school, and one of the feminists threatening to castrate Jean-Paul with her Swiss Army knife. The group divided into two factions, with one lot refusing to speak to, or sit with, the others. It rained incessantly.

The last night should have been spent in a luxury hotel recovering from the ardours of trekking. Instead it was spent with the group split between a pair of whorehouses. One had no bathroom of any kind and the most prudish of the women was reprimanded by the village policeman for squatting in the street, while the other had an outhouse that was occupied by a monkey chained to the lavatory seat.

Sometimes you need a truly dreadful trip to fully appreciate the good ones!