What is the best way to start a business in Thailand? Here are two suggestions:

If you are selling something, then I suggest selling something very unique in town, because Thai people love to run shopping malls and they are almost completely satisfied there!

If you are opening a store I suggest you serve the Chinese, open a Chinese restaurant in a place where there is a concentration of Chinese, for example near a school with a large number of Chinese students, with pure Chinese flavors, because Thai food does not come out well, it's either sweet, spicy or fishy. That's why many international students like to cook their own Chinese food in their dormitories.