There are huge variety of tours offered for visitors to Thailand. Some plan a complete day-to-day itinerary, others just flights and accommodation, and the rest will plan a trip around a particular theme e.g. scuba diving

Unless you're particularly nervous about going independently, day-to-day tours are basically unnecessary. Thailand is an easy country to travel in, and pre-arranged tours are expensive, inflexible and restrict opportunities for meeting the local people.

If you have a particular interest, themed tours' are a good idea as they will often provide experiences that are difficult if not impossible to do independently. Many companies are specialists in one particular field, and so their tours can be well worthwhile. These are often only a few days long, so they leave time for other activities as well.

In the high season (roughly Nov - Feb, and August) the more popular places will fill up very quickly so it's worth making your reservation before you travel. Khao San road is busier at this time of year, but with a bit of searching it's always possible to find a room. It's virtually impossible to reserve a room in a Khao San Road

guesthouse in advance. At other times of year it's not really necessary to book ahead, though it may get you cheaper prices.

How much time should I spend in Thailand

This really depends on what you want to see
while you are there.
The main highlights of Bangkok can be seen in a couple of days, but seeing everything in Bangkok and nearby could take weeks.



Two weeks is enough time for Bangkok, Chiang Mai



and a beach resort.



More time could be spent island hopping in the South or visiting the ruins and temples in the north at Sukhothai, Ayuthaya etc...

What should I take with me

Generally, as little as possible.
A good guidebook is basically essential, but almost everything that can be found in western countries can also be found in Thailand, and it's likely to be cheaper too.
Don't bother stocking up on things like camera films, soap, shampoo etc... because it's completely unnecessary and only means you have to carry more.
If you bring a lot with you, you'll quickly regret it as the heat makes carrying a heavy load very difficult.
Some things though, such as sunglasses, are better brought from home as the quality is likely to be better than you can get in Thailand.

Jumpers and jackets

Jumpers and jackets are completely unnecessary for most of Thailand at most times of year.
The exception is in the North during the cool season Nov to Feb when it can get cold.
Jeans are not a great thing to bring, as the hot and sticky weather can make them uncomfortable.
They also are heavy and take ages to dry
............................bring more lightweight clothes instead.

If you plan on going trekking in the north during the cool season,
a sleeping bag is definitely necessary (they can be bought / rented in Chiang Mai).
Elsewhere, the weather is much warmer and so you don't need one.
A mosquito net is very worthwhile.

Very effective mosquito repellent lotion

You can purchase effective mosquito repellent lotion in most supermarkets throughout Thailand, which is much more effective than that brought from abroad.

What time of year is best to go

This really depends on personal preference, as all parts of the year have relative advantages and disadvantages.
The best Season is between November and March as this is when Thailand is not quite so hot as the rest of the year.
April, May and June can get very hot. July to October is the rainy season, but September and October are much more rainy than July and August.
There are significant variations in the weather in different parts of Thailand.
November to March is the tourist high season and this means flights and accommodation are more expensive, and popular places are likely to be booked out quickly.
Peak times are at Christmas, New Year and the Thai new year (mid-April).
There's considerably fewer tourists around in April to June, as it's simply too hot for some people at this time of year
occasionally over 40 degrees centigrade,
normally around 32 - 34).
The rainy season also has fewer tourists, as the regular tropical downpours put people off.

It's also worth considering what you want to see and do while you are there, as some are only possible at some times of year - scuba diving off some of the islands, certain festivals etc...

What footwear is it best to bring

If you're planning to do any trekking or hiking, decent boots or trainers are essential.
For everyday wear, some people prefer boots/trainers, others sandals. Most Thai people wear sandals all the time, and they have the advantage of being easy to take on and off, keep your feet cooler, and are better during the rainy season.
Cheap sandals are widely available in Bangkok and elsewhere.