Cold-mailing is something very simple but sometimes as a beginner you can make mistakes and some of them can cost you the reputation of your domain name in addition to wasting your time.
Things to absolutely ban in cold-mailing:
Contacting a lot of people from the same company We've seen it several times on Emelia, campaigns on listings of 300 people from the same company, on the same domain name, 99% of the time you'll go to spam after 10 mails, you may not even get bounces, just no opening. Because after a few mails the servers of this company understood that you were spamming several of their collaborators and therefore blocked your mails.
Send 1000 mails per day with one mailbox Even though some of your hosting companies may mark in their documentation that you can send up to 1000 or 2000 mails per day, often, in truth, they will block you before, and even if they don't, you risk damaging the reputation of your domain name and ending up in spam.
Things to avoid in cold-mailing:
Put images Popularized by some a few years ago, besides the fact that it can look a bit cheap now (and that depending on whether the person opens on mobile or desktop the rendering can be different), it is mostly that it weighs down your email and the heavier your email is the more it can go to spam. That being said, to add an image there are two ways to do it, either you have your image hosted somewhere and in Emelia you just put the link of the image in the insert that opens when you press the image button. So the image doesn't weigh in the mail (but it makes a link anyway, we'll come back to that later). Or import the image via the button "Upload" in the image insert of the editor and there it weighs in your mail so it is not good. We left the choice because it was requested by customers but in itself it is not a good practice.
Put attachments Overall same principle as images, it weighs down your mail so it is not a good practice, it is better to put a link to a google drive or another file host. We still put the functionality in Emelia but only one attachment max
Too little spacing of your email steps It's up to you to choose your approach, you may be inclined to tighten your steps to be more "aggressive", it's a strategy, if you are comfortable then why not. But keep in mind that if it is too aggressive then it is often there that on all your listing there is likely to be one or someone who will take the time to report your mail and so there it is not good.
Having too many links An email without a link will have a better deliverability, that being said, obviously you need to convert and it's not always via a response that you want to do it, sometimes it's via an appointment on a calendly and a visit to your site. But try to choose which Call to Action you want and then push only to it in your mail.
A couple of things about links:
Avoid URL shorteners, bit.ly etc, for the hosting providers it is ultra suspicious
Avoid links to non-secure URLs (that don't have HTTPS)
Obviously, avoid links that don't work