Jenn Junod builds a flow chart:
From a structural perspective you can think of data as existing on a continuum or gradient: on the one side, there’s highly structured data, like customer profiles. Each customer has a known name, address, phone number, and we can expect those to fall within certain formatting constraints. For example, a phone number will always be a set of numbers and special characters. On the other side, there’s unstructured data: the contents of an email, for example, are unstructured.
The shape of the data should define what kind of software you use to store and manipulate it.
Read on for several questions along these lines and recommendations based on your answers.