Please find a collection of tips, tricks and how to instructions.
More:
How do I enable/disable the save to SharePoint dialog?
How does OnePlaceMail check for duplicate emails?
How to filter the folder structure of a library/list in the navigation tree of OnePlaceMail
How do I stop the prompt for Office 365 credentials?
Why does column mapping work only for some columns?
Using folders to capture metadata (location level defaults)
OnePlaceMail email content type in different languages
How does OnePlaceMail check for duplicate emails