Separate the commercial issue from the legal one
Ask what each side actually needs to keep trading. The answer is usually narrower, and easier to solve, than the claims on paper suggest.
Put a realistic number on exposure
Both parties tend to overestimate their position. An honest range for likely outcomes, legal costs included, makes settlement far easier to reach.
Design the next contract now
The best settlements include a better framework for the future, so the same disagreement cannot happen twice.