How do you set up Instantly to avoid the spam folder?

I usually send around 21 emails per day from one mailbox, divided into 7 new emails and 14 follow-ups. This setup works well for me.

I send different types of emails and usually get a good number of replies. However, some of my emails are currently landing in spam.

What are the best Instantly settings I should use to improve deliverability and avoid emails going to spam?

I’m already sending a relatively low number of emails compared to the usual limits, so I’d like to understand what settings I should adjust.