Complexity can be overwhelming. That’s why seasoned dealmakers often rely on
1. ‘Framework/detail’ negotiation.First you work out broad features of the deal, then later you (or your lawyers, aides, and subordinates) workout the specifics. For example, most executives work out a term sheet then translate it into a contract.
2. Single Negotiating Text. A related tool is a Single Negotiating Text. Here you put your full proposal (sketched or detailed) in a single document. Putting the entire offer in one place invites everyone to see the whole deal, to propose tradeoffs, and avoid naively combative arguing over one issue at a time. It’s the tradeoffs between topics that can foster much better deals
3. Fractionating.  Another way to manage complexity better: ‘Fractionating’ where you have several committees negotiate concurrently on different blocks of issues.