1. Avoid sending unsolicited emails: Sending unsolicited emails is a common reason for your emails to land in spam. So, make sure you only send emails to people who have opted-in to receive them.

2. Control the controllable: There are certain things that are not in your control when it comes to email service providers, like the IP address used to send emails. However, you can control the subject line and email body to avoid being marked as spam.

3. Check your email subject line and body for spam score: You can use various online tools to check your email subject line and body for a spam score. Make sure the score is less than 90 to avoid being marked as spam.

4. Test your email for spam: You can also use tools to test your complete email for spam and look at the report. Correct the things you can, like DKIM and DMARC.

5. Send legitimate and personal emails: Make sure you are sending relevant and personalized emails that the receiver would want to open and read.

By following these steps, you can increase the chances of your emails landing in the inbox rather than the spam folder. However, there is no guarantee that your emails will never land in spam as the email receiving server has its own rules and logic to mark emails as spam.