If you were to compare them, as high a percentage of different from the others as possible. Try to think of it as if it was a single email, a reply, a dialogue. So it could be different by using the recipients profile (see e.g. all CRM field data) and by how you talk uniquely with one another in this dialogue (which can be partially achieved by random content (the brain throws random suitable phrases in natural dialogue as well, and it is not always perfect and somewhat, repetitive among different dialogues)), and then keep thinking along these lines to come as close as possible to the uniqueness.can you explain a little further? Do you mean each email should be unique/personalised in some way?
This can be done partially by having even the mailto: URLs constructed with random subject lines. The other important factor is to become early a contact in the recipients address book. Remember the many guides to 'whitelisting' (really only re the address book and out of spam folder, has nothing to do with IP whitelisted network) that many good providers have and htat many good marketers make their subscribers follow when they are supposed to confirm before they get their signup bonus.I think here is the secret.
EE is definitely commercial email, bulk email, ecommerce, internet marketer email and transactional. And they have different IP blocks (quality). But it is not whitelisted. So if you look at the big players who have the personal/individual (non-company) mailboxes for the masses (gmail, yahoo, etc), then ESPs like EE (incl sendgrid, amazonses, sparkpost, etc), then the company IP blocks (definitely commercial, whether sending or not), and the few whitelisted networks (usually only for DOI, and with strict rules and very long build-up periods, and regular re-checks to maintain membership), then you can see the difference.sent from elastic email. Assume it's a whitelisted IP network as that's their core offering.
However, gmail and gsuite still would look at the other above factors, and no-interaction-emails would still be classed down. Sometimes it might be easier to build your own whitelisted IP block than to try to join one (e.g. if they deny membership). If truly whitelisted, your email will bypass the spam filter of many providers unchecked, faces less speed limits, and lands in the inbox. Only complaints can harm (though DOI defends against them mostly) or serious screw-ups (i.e exceptional mistakes or tech fails).