Always remember: The quality of your relationship with a supplier is shaped and defined by the contract that you and the supplier sign. So obviously you want to have comprehensive, well-written contracts with all of your suppliers.
If you work at a large company, you will have plenty of resources within the company supporting your efforts to negotiate good contracts. You will have help from legal, purchasing, finance, and other departments.
But in the final analysis, the contracts you sign are a reflection of your personality. If you are tough, honest, and fair, you will negotiate contracts that are tough, honest, and fair. If you are weak, disingenuous, and trying to create an unfair advantage, the contracts you negotiate will come back to haunt you and your organization for a long, long time.
When I was hired as the CIO of General ...