Best practice for params key names for mapping to models

What’s the best practice for naming keys in the params array so they map
most efficiently to models?

There isn’t an equivelent of ActiveRecord for mapping params keys to
models, so I’m wondering if there is a best practice.

I’m writing an addressbook with a form that has mixed models on it and
multiple one-to-many relations. I’m processing new records in the
create method and updating records in the update method. I’d like to
have one method to handle both create and update (an attempt to dry up
my code).

I’m using my own naming convention in params for new records, the model
name with “new_” appended. I’m thinking how I might be able to right
this all-in-one method (both create and update method). My hunch is
that a proper naming scheme for the params keys would make it easier.