You can have the best website in your sector, the cleverest ad campaign, the slickest funnel. If you don't know what a customer costs you to acquire and what one is worth, you're flying blind, and no amount of clever fixes the fact that you can't tell whether any of it is working.

If you run a small business and you write your own sales emails, this one’s for you. It’s a tiny change, it costs nothing, and in my experience it’s one of the highest-impact tweaks you can make to your outreach.