Hi Eric. This is a great question. And a noble endeavor to desire to help others with debt management problems.
When negotiating to settle debt there are several key factors. The first is the type of debt.
Secured debt is particularly difficult to negotiate, as the lender has security they have less to lose. For unsecured debt it depends on both the type of debt and the institution which holds the debt. Non-contractual debt with local institutions will generally be easier to negotiate.
Where the debt is in the collection process also matters. Older debt, especially debt passed through multiple collection agencies, becomes more and more negotiable as it moves further from its source.
There is a lot you can learn about debt settlement which can be useful in helping others. In addition to knowing how and when to negotiate it is very important to know the laws so you can help people avoid inappropriate debt collection practices. Good luck!