I would like to hear your experiences about establishing fertile business relations with Thais. How best to do it?

In my experience it’s of great importance to spend time to get to know each other and establish trust/friendship before you begin the actual process of negotiating the terms of your business relation.

This is of course true in any country, but even more so in Thailand, I think. Start by becoming friends and then do business, seems to be the Thai way.

Maybe so, because 82% of all Thais think it’s ok to cheat in business relations! (This was the result of a survey that was printed in the Bangkok Post a couple of years ago). This may create the need to spend more time together before trust is established.

What are your experiences in regards to establishing fertile business relations with Thais?

I wouldn't go into business with a Thai - or a foreigner. There are too many cases here of dishonesty and too few examples of fair redress. You will never be equal to a Thai partner, whatever your contract might say.

As OP posted basically the same topic 3 days ago, I've closed the other one: