Background
My startup is relying heavily on contacts, which I trust. If I improved my way of assessing whether a new contact is trustworthy or not, I believe my startup would be more successful. Sometimes I have for example dumped potential customers, by setting the price so high that it was unrealistic, just because I have a bad feeling about them. I could not even quite justify the reasons for my bad feeling myself, and much less explain them to others.
Question
Are there any tricks I could use to assess the trustworthiness, which I could use in addition to my gut feeling?
The tricks I already use are things like checking the background and using my network to try to get information about the persons history. I also use Google, what I am after is more how to do this in one-to-one interaction.
I would also be interested in any practical guides on this, I know a lot of the theory being trust.