How do I build offers and guarantees for my cold email clients on a kickoff call?

The simplest way is not to give clients too much control or oversight of your cold email process, because if they were good at cold email they'd do it themselves. They usually lack marketing ability, think they have a good niche and angle, but are often mistaken. I frame cold email as a game: I throw a ton of stuff at the wall until something sticks, testing different offers and pitches without using the client's company name or information, so they don't worry about reputation or branding. When I find a winner, I bring it back to flesh out and verify feasibility. Basically, just let me do my thing and stop complaining about ICP or language; we need to try a lot to find what actually works.