Start with the deal, not the object model
The fastest way to damage a CPQ programme is to turn the current spreadsheet into fields and automation. We start by modelling the commercial conversation: what the rep sells, what finance must approve, which product combinations are illegal and which exceptions are common enough to deserve a controlled path.
Separate price construction from discount governance
Base price, usage tiers, subscription terms, uplifts, bundles and region rules should not be mixed with approval logic. This makes it easier to explain the quote to finance and easier to test the quote when a new catalogue version ships.
Design for exceptions
Enterprise quotes always contain exceptions: grandfathered rates, non-standard ramps, delayed provisioning or one-off credits. Good CPQ design does not pretend these never happen. It captures them, routes them and makes their financial effect visible before signature.
What good looks like
A resilient pricing engine can explain every number on the quote, reproduce the calculation in an audit, and give sales a fast path without removing governance. That is the difference between a CPQ implementation and an operating system for revenue.
Bring the hard part to a senior Salesforce engineering team.