Outgoing email going to recipient spam folder

Outgoing email going to recipient spam folder

I am having a big problem that my emails from Zoho almost invariably go to the spam folder of my recipient unless they have put me on their white list.  Is there any way to address this?  I work in sales, so often I am responding to emailed inquiries from people who have no previous contact with me.  It is a big problem if all of my replies go to spam.