For tourists coming to Thailand for the first time, a major question is what should I see, or where should I go?
The answer may very well be dependent on how much time you have to spend in Thailand.
Thailand is a very large and diverse country.
Getting from the south all the way to the north, eats up days traveling.
It is crucial to understand your timeline, then plan your itinerary to maximize seeing the most you can.
Bangkok is where you will probably land and worth spending a few days to get accustomed to being in Thailand.
Grand Palace/other major temples, Chinatown, Chao Praya River cruise and a host of other attractions can easily take up 3 or 4 days.
From Bangkok you have to decide your travel plans. Nearby you will find Pattaya.
Pattaya has a host of things to see and do including a short ferry to Koh Larn which has a nice beach area, watersports and other things.
Pattaya also has some world class nightclubs with famous DJ’s.
Close yet is Hua Hin, a very laid back beach town if you are looking for rest and relaxation.
If you plan to venture south to the Islands, you can either fly, which will save travel time or take a bus, train, or private transport.
Phuket, Krabi, Railay Beach, Maya Bay and a host of island options away you.
It would be very easy to spend 5+ days exploring all the islands and for most tourists, visiting the islands is the highlight of their holiday here.
If you decided to head north from Bangkok, there is Chiang Mai and Chiang Rai. An area that has many attractions, temples, waterfalls, etc. Be sure to research if Chiang Mai/Chiang Rai is for you?
There are many other areas, that are all accessible if you have the time to visit.
Kanchanaburi, Isaan, Pai, and northern Thailand have a better peek at the real Thailand.
When you plan your itinerary make sure you account for travel days and the day getting back to the airport.
Read and research all you can, then plan out what works best for you in the holiday time you have.
Good luck.