django: best practice way to get model from an instance of that model

my_model = type(my_instance)

To prove it, you can create another instance:

my_new_instance = type(my_instance)()

This is why there's no direct way of doing it, because python objects already have this feature.

updated...

I liked marcinn's response that uses type(x). This is identical to what the original answer used (x.__class__), but I prefer using functions over accessing magic attribtues. In this manner, I prefer using vars(x) to x.__dict__, len(x) to x.__len__ and so on.

updated 2...

For deferred instances (mentioned by @Cerin in comments) you can access the original class via instance._meta.proxy_for_model.

my_new_instance = type(my_instance)()