Wonderful blog post with useful tactics regarding successful business. In my view point:

• Whenever you do a business with XYZ, your way of speaking / talking should be extra polite.
• Client / customer towards you is always right so give him value at the initial gathering. But don't spare during finalizing the terms. At that point you should tactfully consider the terms which will not give you any loss or ambiguity at later stage.
• Budget should be planed in advance and there must me 10-12% margin in any case.

There of lot of things which can be accepted / rejected during R&D. But the best Project manager will never loose any project(If the other is really a customer or a company).
All the best @rivalhw for your future projects. Good luck and Stay Blessed!