If you want to travel comfortably, prepare your luggage well. Here is the top 10 of essentials to bring (excluding official documents):
A book or e-book for the flight or train journeys
A small notebook to write down your travel memories
Light clothing: T-shirts, shorts, lightweight trousers
A down jacket, warm coat, and waterproof trench coat if heading to the mountainous north
Backpacks to carry water and personal items during hikes
Appropriate clothing for visiting Buddhist temples (long trousers, long-sleeved shirt or cardigan, sarong)
A digital camera to capture Thailand’s magnificent sites and moments shared with family
Sunglasses and a swimsuit for beach outings
Mosquito repellent
A first-aid kit and medication for allergies
SPF 50 sunscreen, sunglasses, hat or cap, and after-sun lotion