How to maintain tone and style across departments or campaigns?

Tone and style consistency requires documented standards and governance processes. Create an email-specific style guide that covers voice attributes (friendly vs. formal, playful vs. serious), writing conventions (sentence structure, word choices to use and avoid), formatting standards (header styles, bullet point usage), and examples of good and bad executions. The guide should be specific enough to create alignment without being so restrictive it kills creativity.

Master templates with locked elements enforce visual consistency: header, footer, color palette, and typography are standardized; only content areas are editable. This prevents well-intentioned but off-brand customization. Supplement templates with a component library of approved modules (CTAs, image treatments, callout boxes) that teams can assemble while staying on-brand.

Process enforcement matters as much as documentation. Implement review workflows where emails pass through brand/copy review before deployment. For larger organizations, designate brand stewards who can approve deviations and ensure guidelines evolve appropriately. Regular audits catch drift over time. Style guides only work if people use them; governance processes only work if they're efficient enough that people don't route around them. Balance thoroughness with practicality.