You wrote a good email, cut what did not need to be there, and pressed send. Almost nobody opened it. The subject line was not the problem, and neither was your list. Somewhere between your outbox and their inbox, your email quietly failed a test you never knew existed. That test is email deliverability, and six checks catch most of what blocks it. One habit protects every email you send after. Here is what decides whether your writing gets seen at all, before a single reader has the chance to judge it.
