Some Thai food is very spicy, so if you do not like spicy food, tell the waiter/cook up front and they will cut down on the spices for you.
You will also find, especially in Bangkok, European/US/Japanese etc. outlets such as Pizza Hut, Kentucky, McDonalds, MK, Sorenson, Fuji, Mister Donut and many others. Central, Tesco, Big C, Carrefour and other hypermarkets also have restaurants within them.
But you must really try a traditional Thai riverside restaurant for a taste experience topped by no other.
There are many exotic fruits available, such as Jackfruit, Rambuten, Mango, Papaya and many more. You have not tasted Coconut juice until you have had a fresh, straight off the tree Coconut, drunk with a straw through a hole in the coconut shell, you can get one for as little as 10 bahts (about 20p GBP).
Many markets sell coke, orange juice etc. In ice filled plastic bags with straws and handles on the bags, around 10 bahts each.
Sausages, fish balls and spicy chicken on sticks are commonly found on street sellers trolleys.