When in Rome, do as the Romans. When in Thailand, do as the Thaïs do. Nothing will endear you more to the local people in Thailand is knowing how to eat like they do.
Most Thai meals consist of meat, rice and vegetables. I know this is a generalization but I am talking about most of the meals. For meals like this you will only be given two utensils, a spoon and a fork. There are also fried noodle dishes that are also eaten with spoon and fork.
The spoon is used to eat with and the fork is basically a shovel used to push food on the spoon. The meat will cut in bite size pieces so there is no need for a knife. Once you get used to it, it is a very easy way of eating.
A knife is only needed if you order something like a steak or have some bread that needs buttering. But, this is not Thai food.
Chopsticks are primarily used when eating soup. One of the Thai staples is noodle soup called gwet-ee-ow (your phonetics may differ from mine). This soup can be found on almost every corner in Thailand. It comes with a variety of vegetables, different sized noodles, and different meats. There will be different condiments that can be added; hot chili peppers, crushed peanuts, sugar, vinegar and more. The best thing to do is to add a little and give it a taste and see what else needs to be added. Of course, a spoon is also used to sample the broth.
You can also get back to basics and enjoy some Thai food with no utensils at all. You can call it Thai finger food. Sticky rice, fruits, and vegetables are sometimes easier to eat just by using your fingers. Your girl may peel, break, or share a bite with you and all she will use are her fingers and her teeth. It may not be the most sanitary, but it is delicious and a lot of fun.
And, if you are really brave, you can sample some of the Isaan, or northeast, snacks. You will see many bug carts in Bangkok and Pattaya displaying crickets, ants, beetles, silkworms and other delicacies. If you can down these, you will endear yourself to your Isaan friends forever.
So, as you can see, there are just a few things to learn to eat like the Thaïs do. Eat the local food and do it in the proper way and you will enjoy your holiday all the more.