What's the best practice to show a node's fields in different regions?
Not exactly sure why you want to have every single field as a separate block? That's pretty inefficient, if nothing else.

To have one or two additional blocks, you can use an Entity view block provided by ctools module. It will take the current node and display it in a certain view mode. Of course that will be painful to maintain if every field is separate, but I don't really see why you would want to do that?