According to Xneelo:

Spam is defined as an email that is sent to a large number of recipients, where the recipients have not explicitly given permission to be emailed and the purpose of the email is to solicit a commercial action, e.g. selling a product.

Emails have to be hosted somewhere – they get hosted on an email server. Practically, when you send an email from your email account, it will get sent from your email server to the recipient’s (who you sent an email to) email server. Before we look into what we can do, let’s understand how emails work behind the scenes once you have hit SEND.

Each email server will have its unique spam filters and filtering techniques. Spammers adapt and evolve regularly, so SPAM filters need to update and evolve regularly. For this reason, it’s impossible to give a complete set of rules to guarantee that your emails will always be SPAM FREE.

However, there are specific steps that you can take in your emails to lower the chances of your email being classed as SPAM by SPAM filters.

Steps to take:

• Don’t use capitals where it is not necessary.
• Avoid punctuation in the subject line of your email.
• Try not to overuse punctuation in the body of your email. e.g.?!!
• Do not to substitute letters with numbers in your body, e.g. w3b h0sting
• Use proper grammar and avoid spaces between letters. e.g. e m a i l
• Try not to use many different font colours in your email.
• Avoid using very common Call-to-Action phrases found in SPAM emails. E.g. Click Here, Buy Now, As Seen On, Money Making, Get Paid, Make Cash, Pre-Approved, Hot Deal, Satisfaction Guaranteed, Lowest Prices, Save Big, etc.
• Avoid the overuse of images in your email. The best practice is; generally, you should have two lines of text for every image.
• Ensure that the IP address of the device you are sending from is not on a SPAM Blacklist. You can check over here.

Wrapping Up

 These are just some steps that you can take to ensure that your email never gets flagged as SPAM. However, it’s important to note that SPAM filters are dynamic, and even doing all the steps above won’t guarantee that your email is not regarded as SPAM.

We would suggest that if you are sending an email and not receiving a response in the expected timeframe, follow up with the recipient as the email might be in the SPAM Bucket.

If this issue keeps occurring with the same email address, you could also ask the recipient to whitelist your email address. This will ensure that your email will always go through.